diff options
author | Daniel Friesel <derf@finalrewind.org> | 2019-11-01 21:19:25 +0100 |
---|---|---|
committer | Daniel Friesel <derf@finalrewind.org> | 2019-11-01 21:19:25 +0100 |
commit | 1082a82fabd84fb2f23f182fa7f9ed76db9071d6 (patch) | |
tree | b85c24d29f1a8a612fec9e0325db8d0ddb6b788d | |
parent | 2d62ccb5bb0f8cea5d6a75e6fd74a7d3cdbd0c69 (diff) |
MPU9250: Add SparkFun constants and non-raw readout of Accel and Gyro
-rw-r--r-- | include/driver/mpu9250.h | 276 | ||||
-rw-r--r-- | src/app/mpu9250_motionlog/Makefile.inc | 2 | ||||
-rw-r--r-- | src/app/mpu9250_motionlog/main.cc | 66 | ||||
-rw-r--r-- | src/driver/mpu9250.cc | 123 |
4 files changed, 450 insertions, 17 deletions
diff --git a/include/driver/mpu9250.h b/include/driver/mpu9250.h index e362994..3ebcb17 100644 --- a/include/driver/mpu9250.h +++ b/include/driver/mpu9250.h @@ -1,27 +1,287 @@ #ifndef MPU9250_H #define MPU9250_H +/* +Copyright (c) 2016 SparkFun Electronics, Inc. +Copyright (c) 2019 Daniel Friesel + +Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. +*/ + + + class MPU9250 { + public: + enum accel_fsr_e { + INV_FSR_2G = 0, + INV_FSR_4G, + INV_FSR_8G, + INV_FSR_16G, + NUM_ACCEL_FSR + }; + enum gyro_fsr_e { + INV_FSR_250DPS = 0, + INV_FSR_500DPS, + INV_FSR_1000DPS, + INV_FSR_2000DPS, + NUM_GYRO_FSR + }; + private: MPU9250(const MPU9250 ©); unsigned char const address = 0x68; unsigned char txbuf[3]; unsigned char rxbuf[8]; signed int getWordReg(unsigned char const regBase); + bool gyroStandby; + accel_fsr_e accel_fsr; + gyro_fsr_e gyro_fsr; public: - MPU9250() {} + + enum mpu9250_register { + MPU9250_SELF_TEST_X_GYRO = 0x00, + MPU9250_SELF_TEST_Y_GYRO = 0x01, + MPU9250_SELF_TEST_Z_GYRO = 0x02, + MPU9250_SELF_TEST_X_ACCEL = 0x0D, + MPU9250_SELF_TEST_Y_ACCEL = 0x0E, + MPU9250_SELF_TEST_Z_ACCEL = 0x0F, + MPU9250_XG_OFFSET_H = 0x13, + MPU9250_XG_OFFSET_L = 0x14, + MPU9250_YG_OFFSET_H = 0x15, + MPU9250_YG_OFFSET_L = 0x16, + MPU9250_ZG_OFFSET_H = 0x17, + MPU9250_ZG_OFFSET_L = 0x18, + MPU9250_SMPLRT_DIV = 0x19, + MPU9250_CONFIG = 0x1A, + MPU9250_GYRO_CONFIG = 0x1B, + MPU9250_ACCEL_CONFIG = 0x1C, + MPU9250_ACCEL_CONFIG_2 = 0x1D, + MPU9250_LP_ACCEL_ODR = 0x1E, + MPU9250_WOM_THR = 0x1F, + MPU9250_FIFO_EN = 0x23, + MPU9250_I2C_MST_CTRL = 0x24, + MPU9250_I2C_SLV0_ADDR = 0x25, + MPU9250_I2C_SLV0_REG = 0x26, + MPU9250_I2C_SLV0_CTRL = 0x27, + MPU9250_I2C_SLV1_ADDR = 0x28, + MPU9250_I2C_SLV1_REG = 0x29, + MPU9250_I2C_SLV1_CTRL = 0x2A, + MPU9250_I2C_SLV2_ADDR = 0x2B, + MPU9250_I2C_SLV2_REG = 0x2C, + MPU9250_I2C_SLV2_CTRL = 0x2D, + MPU9250_I2C_SLV3_ADDR = 0x2E, + MPU9250_I2C_SLV3_REG = 0x2F, + MPU9250_I2C_SLV3_CTRL = 0x30, + MPU9250_I2C_SLV4_ADDR = 0x31, + MPU9250_I2C_SLV4_REG = 0x32, + MPU9250_I2C_SLV4_DO = 0x33, + MPU9250_I2C_SLV4_CTRL = 0x34, + MPU9250_I2C_SLV4_DI = 0x35, + MPU9250_I2C_MST_STATUS = 0x36, + MPU9250_INT_PIN_CFG = 0x37, + MPU9250_INT_ENABLE = 0x38, + MPU9250_INT_STATUS = 0x3A, + MPU9250_ACCEL_XOUT_H = 0x3B, + MPU9250_ACCEL_XOUT_L = 0x3C, + MPU9250_ACCEL_YOUT_H = 0x3D, + MPU9250_ACCEL_YOUT_L = 0x3E, + MPU9250_ACCEL_ZOUT_H = 0x3F, + MPU9250_ACCEL_ZOUT_L = 0x40, + MPU9250_TEMP_OUT_H = 0x41, + MPU9250_TEMP_OUT_L = 0x42, + MPU9250_GYRO_XOUT_H = 0x43, + MPU9250_GYRO_XOUT_L = 0x44, + MPU9250_GYRO_YOUT_H = 0x45, + MPU9250_GYRO_YOUT_L = 0x46, + MPU9250_GYRO_ZOUT_H = 0x47, + MPU9250_GYRO_ZOUT_L = 0x48, + MPU9250_EXT_SENS_DATA_00 = 0x49, + MPU9250_EXT_SENS_DATA_01 = 0x4A, + MPU9250_EXT_SENS_DATA_02 = 0x4B, + MPU9250_EXT_SENS_DATA_03 = 0x4C, + MPU9250_EXT_SENS_DATA_04 = 0x4D, + MPU9250_EXT_SENS_DATA_05 = 0x4E, + MPU9250_EXT_SENS_DATA_06 = 0x4F, + MPU9250_EXT_SENS_DATA_07 = 0x50, + MPU9250_EXT_SENS_DATA_08 = 0x51, + MPU9250_EXT_SENS_DATA_09 = 0x52, + MPU9250_EXT_SENS_DATA_10 = 0x53, + MPU9250_EXT_SENS_DATA_11 = 0x54, + MPU9250_EXT_SENS_DATA_12 = 0x55, + MPU9250_EXT_SENS_DATA_13 = 0x56, + MPU9250_EXT_SENS_DATA_14 = 0x57, + MPU9250_EXT_SENS_DATA_15 = 0x58, + MPU9250_EXT_SENS_DATA_16 = 0x59, + MPU9250_EXT_SENS_DATA_17 = 0x5A, + MPU9250_EXT_SENS_DATA_18 = 0x5B, + MPU9250_EXT_SENS_DATA_19 = 0x5C, + MPU9250_EXT_SENS_DATA_20 = 0x5D, + MPU9250_EXT_SENS_DATA_21 = 0x5E, + MPU9250_EXT_SENS_DATA_22 = 0x5F, + MPU9250_EXT_SENS_DATA_23 = 0x60, + MPU9250_I2C_SLV0_DO = 0x63, + MPU9250_I2C_SLV1_DO = 0x64, + MPU9250_I2C_SLV2_DO = 0x65, + MPU9250_I2C_SLV3_DO = 0x66, + MPU9250_I2C_MST_DELAY_CTRL =0x67, + MPU9250_SIGNAL_PATH_RESET = 0x68, + MPU9250_MOT_DETECT_CTRL = 0x69, + MPU9250_USER_CTRL = 0x6A, + MPU9250_PWR_MGMT_1 = 0x6B, + MPU9250_PWR_MGMT_2 = 0x6C, + MPU9250_FIFO_COUNTH = 0x72, + MPU9250_FIFO_COUNTL = 0x73, + MPU9250_FIFO_R_W = 0x74, + MPU9250_WHO_AM_I = 0x75, + MPU9250_XA_OFFSET_H = 0x77, + MPU9250_XA_OFFSET_L = 0x78, + MPU9250_YA_OFFSET_H = 0x7A, + MPU9250_YA_OFFSET_L = 0x7B, + MPU9250_ZA_OFFSET_H = 0x7D, + MPU9250_ZA_OFFSET_L = 0x7E + }; + + enum interrupt_status_bits { + INT_STATUS_RAW_DATA_RDY_INT = 0, + INT_STATUS_FSYNC_INT = 3, + INT_STATUS_FIFO_OVERFLOW_INT = 4, + INT_STATUS_WOM_INT = 6, + }; + + enum gyro_config_bits { + GYRO_CONFIG_FCHOICE_B = 0, + GYRO_CONFIG_GYRO_FS_SEL = 3, + GYRO_CONFIG_ZGYRO_CTEN = 5, + GYRO_CONFIG_YGYRO_CTEN = 6, + GYRO_CONFIG_XGYRO_CTEN = 7, + }; + + int const MPU9250_GYRO_FS_SEL_MASK = 0x3; + + int const MPU9250_GYRO_FCHOICE_MASK = 0x3; + + enum accel_config_bit { + ACCEL_CONFIG_ACCEL_FS_SEL = 3, + ACCEL_CONFIG_AZ_ST_EN = 5, + ACCEL_CONFIG_AY_ST_EN = 6, + ACCEL_CONFIG_AX_ST_EN = 7, + }; + + int const MPU9250_ACCEL_FS_SEL_MASK = 0x3; + + enum accel_config_2_bits { + ACCEL_CONFIG_2_A_DLPFCFG = 0, + ACCEL_CONFIG_2_ACCEL_FCHOICE_B = 3, + }; + + enum pwr_mgmt_1_bits { + PWR_MGMT_1_CLKSEL = 0, + PWR_MGMT_1_PD_PTAT = 3, + PWR_MGMT_1_GYRO_STANDBY = 4, + PWR_MGMT_1_CYCLE = 5, + PWR_MGMT_1_SLEEP = 6, + PWR_MGMT_1_H_RESET = 7 + }; + + enum pwr_mgmt_2_bits { + PWR_MGMT_2_DISABLE_ZG = 0, + PWR_MGMT_2_DISABLE_YG = 1, + PWR_MGMT_2_DISABLE_XG = 2, + PWR_MGMT_2_DISABLE_ZA = 3, + PWR_MGMT_2_DISABLE_YA = 4, + PWR_MGMT_2_DISABLE_XA = 5, + }; + + enum int_enable_bits { + INT_ENABLE_RAW_RDY_EN = 0, + INT_ENABLE_FSYNC_INT_EN = 3, + INT_ENABLE_FIFO_OVERFLOW_EN = 4, + INT_ENABLE_WOM_EN = 6, + }; + + enum int_pin_cfg_bits { + INT_PIN_CFG_BYPASS_EN = 1, + INT_PIN_CFG_FSYNC_INT_MODE_EN = 2, + INT_PIN_CFG_ACTL_FSYNC = 3, + INT_PIN_CFG_INT_ANYRD_2CLEAR = 4, + INT_PIN_CFG_LATCH_INT_EN = 5, + INT_PIN_CFG_OPEN = 6, + INT_PIN_CFG_ACTL = 7, + }; + + int const INT_PIN_CFG_INT_MASK = 0xF0; + + int const MPU9250_WHO_AM_I_RESULT = 0x71; + + enum ak8963_register { + AK8963_WIA = 0x0, + AK8963_INFO = 0x1, + AK8963_ST1 = 0x2, + AK8963_HXL = 0x3, + AK8963_HXH = 0x4, + AK8963_HYL = 0x5, + AK8963_HYH = 0x6, + AK8963_HZL = 0x7, + AK8963_HZH = 0x8, + AK8963_ST2 = 0x9, + AK8963_CNTL = 0xA, + AK8963_RSV = 0xB, + AK8963_ASTC = 0xC, + AK8963_TS1 = 0xD, + AK8963_TS2 = 0xE, + AK8963_I2CDIS = 0xF, + AK8963_ASAX = 0x10, + AK8963_ASAY = 0x11, + AK8963_ASAZ = 0x12, + }; + + int const MAG_CTRL_OP_MODE_MASK = 0xF; + + int const AK8963_ST1_DRDY_BIT = 0; + + int const AK8963_WHO_AM_I_RESULT = 0x48; + + /* Filter configurations. */ + enum lpf_e { + INV_FILTER_256HZ_NOLPF2 = 0, + INV_FILTER_188HZ, + INV_FILTER_98HZ, + INV_FILTER_42HZ, + INV_FILTER_20HZ, + INV_FILTER_10HZ, + INV_FILTER_5HZ, + INV_FILTER_2100HZ_NOLPF, + NUM_FILTER + }; + + MPU9250() : gyroStandby(false), accel_fsr(INV_FSR_2G), gyro_fsr(INV_FSR_250DPS) {} void init(); - int getAccelX() { return getWordReg(59); } - int getAccelY() { return getWordReg(61); } - int getAccelZ() { return getWordReg(63); } - int getGyroX() { return getWordReg(67); } - int getGyroY() { return getWordReg(69); } - int getGyroZ() { return getWordReg(71); } + inline int getAccelX() { return getWordReg(59); } + inline int getAccelY() { return getWordReg(61); } + inline int getAccelZ() { return getWordReg(63); } + inline int getGyroX() { return getWordReg(67); } + inline int getGyroY() { return getWordReg(69); } + inline int getGyroZ() { return getWordReg(71); } + void getRawAccel(int *x, int *y, int *z); + void getRawGyro(int *x, int *y, int *z); + void getRawMagnet(int *x, int *y, int *z); + void getAccel(float *g_x, float *g_y, float *g_z); + void getGyro(float *dps_x, float *dps_y, float *dps_z); void getMagnet(int *x, int *y, int *z); void setAccelEnable(bool x, bool y, bool z); void setGyroEnable(bool x, bool y, bool z); - void setPower(bool sleep, bool gyroStandby); + void setGyroStandby(bool gyroStandby); + void setAccelFSR(accel_fsr_e fsr); + void setGyroFSR(gyro_fsr_e fsr); + void AGSleep(); + void AGWakeup(); + void MagSleep(); + void MagWakeup(); float getTemperature(); }; diff --git a/src/app/mpu9250_motionlog/Makefile.inc b/src/app/mpu9250_motionlog/Makefile.inc new file mode 100644 index 0000000..e273aaa --- /dev/null +++ b/src/app/mpu9250_motionlog/Makefile.inc @@ -0,0 +1,2 @@ +arch_drivers += ,i2c +drivers += ,mpu9250 diff --git a/src/app/mpu9250_motionlog/main.cc b/src/app/mpu9250_motionlog/main.cc new file mode 100644 index 0000000..fc9ac1d --- /dev/null +++ b/src/app/mpu9250_motionlog/main.cc @@ -0,0 +1,66 @@ +#include "arch.h" +#include "driver/gpio.h" +#include "driver/stdout.h" +#if defined(MULTIPASS_ARCH_HAS_I2C) && !defined(DRIVER_SOFTI2C) +#include "driver/i2c.h" +#else +#include "driver/soft_i2c.h" +#endif +#include "driver/mpu9250.h" + +#define UPDATE_MIN(min_val, val) if ((val) < (min_val)) { (min_val) = (val); } +#define UPDATE_MAX(max_val, val) if ((val) > (max_val)) { (max_val) = (val); } + +int main(void) +{ + int ax, ay, az, gx, gy, gz; + int max_ax, max_ay, max_az, max_gx, max_gy, max_gz; + int min_ax, min_ay, min_az, min_gx, min_gy, min_gz; + unsigned char i = 0; + + arch.setup(); + gpio.setup(); + kout.setup(); + + if (i2c.setup() != 0) { + kout << "I2C setup failed" << endl; + return 1; + } + + kout << "I2C setup OK" << endl; + + mpu9250.init(); + + while (1) { + mpu9250.getRawAccel(&ax, &ay, &az); + mpu9250.getRawGyro(&gx, &gy, &gz); + + UPDATE_MIN(min_ax, ax); + UPDATE_MIN(min_ay, ay); + UPDATE_MIN(min_az, az); + UPDATE_MIN(min_gx, gx); + UPDATE_MIN(min_gy, gy); + UPDATE_MIN(min_gz, gz); + UPDATE_MAX(max_ax, ax); + UPDATE_MAX(max_ay, ay); + UPDATE_MAX(max_az, az); + UPDATE_MAX(max_gx, gx); + UPDATE_MAX(max_gy, gy); + UPDATE_MAX(max_gz, gz); + + if (i++ == 200) { + kout << "Temp: " << mpu9250.getTemperature() << endl; + kout << "Min Accel: " << min_ax << " / " << min_ay << " / " << min_az << endl; + kout << "Max Accel: " << max_ax << " / " << max_ay << " / " << max_az << endl; + kout << "Min Gyro: " << min_gx << " / " << min_gy << " / " << min_gz << endl; + kout << "Max Gyro: " << max_gx << " / " << max_gy << " / " << max_gz << endl; + min_ax = min_ay = min_az = 0; + min_gx = min_gy = min_gz = 0; + max_ax = max_ay = max_az = 0; + max_gx = max_gy = max_gz = 0; + i = 0; + } + } + + return 0; +} diff --git a/src/driver/mpu9250.cc b/src/driver/mpu9250.cc index c1ac53d..1c6e02c 100644 --- a/src/driver/mpu9250.cc +++ b/src/driver/mpu9250.cc @@ -6,13 +6,24 @@ #include "driver/soft_i2c.h" #endif +/* +Copyright (c) 2016 SparkFun Electronics, Inc. +Copyright (c) 2019 Daniel Friesel + +Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. +*/ + void MPU9250::init() { // reset to default txbuf[0] = 107; txbuf[1] = 0x80; i2c.xmit(address, 2, txbuf, 0, rxbuf); - arch.delay_ms(1); + arch.delay_ms(100); // enable I2C passthrough to magnetometer txbuf[0] = 55; @@ -23,7 +34,7 @@ void MPU9250::init() txbuf[0] = 0x0b; txbuf[1] = 1; i2c.xmit(0x0c, 2, txbuf, 0, rxbuf); - arch.delay_ms(1); + arch.delay_ms(100); // put magnetometer into continuous measurement mode txbuf[0] = 0x0a; @@ -71,13 +82,53 @@ void MPU9250::setAccelEnable(bool x, bool y, bool z) i2c.xmit(address, 2, txbuf, 0, rxbuf); } -void MPU9250::setPower(bool sleep, bool gyroStandby) +void MPU9250::setGyroFSR(MPU9250::gyro_fsr_e fsr) +{ + txbuf[0] = MPU9250_GYRO_CONFIG; + txbuf[1] = fsr << GYRO_CONFIG_GYRO_FS_SEL; + i2c.xmit(address, 2, txbuf, 0, rxbuf); +} + +void MPU9250::setAccelFSR(MPU9250::accel_fsr_e fsr) +{ + txbuf[0] = MPU9250_ACCEL_CONFIG; + txbuf[1] = fsr << ACCEL_CONFIG_ACCEL_FS_SEL; + i2c.xmit(address, 2, txbuf, 0, rxbuf); +} + +void MPU9250::AGSleep() { txbuf[0] = 107; - if (sleep) { - txbuf[1] = 1<<6; - } - else if (gyroStandby) { + txbuf[1] = 1 << 6; + i2c.xmit(address, 2, txbuf, 0, rxbuf); +} + +void MPU9250::MagSleep() +{ + txbuf[0] = 0x0a; + txbuf[1] = 0; + i2c.xmit(0x0c, 2, txbuf, 0, rxbuf); +} + +void MPU9250::AGWakeup() +{ + txbuf[0] = 107; + txbuf[1] = gyroStandby << 4; + i2c.xmit(address, 2, txbuf, 0, rxbuf); +} + +void MPU9250::MagWakeup() +{ + txbuf[0] = 0x0a; + txbuf[1] = 2; + i2c.xmit(0x0c, 2, txbuf, 0, rxbuf); +} + +void MPU9250::setGyroStandby(bool gyroStandby) +{ + this->gyroStandby = gyroStandby; + txbuf[0] = 107; + if (gyroStandby) { txbuf[1] = 1<<4; } i2c.xmit(address, 2, txbuf, 0, rxbuf); @@ -96,10 +147,64 @@ float MPU9250::getTemperature() return (float)getWordReg(65) / 333.87 + 21; } -void MPU9250::getMagnet(int *x, int *y, int *z) +void MPU9250::getRawGyro(int *x, int *y, int *z) +{ + txbuf[0] = 67; + i2c.xmit(address, 1, txbuf, 6, rxbuf); + + *x = ((signed int) rxbuf[0] << 8) + rxbuf[1]; + *y = ((signed int) rxbuf[2] << 8) + rxbuf[3]; + *z = ((signed int) rxbuf[4] << 8) + rxbuf[5]; +} + +void MPU9250::getRawAccel(int *x, int *y, int *z) +{ + txbuf[0] = 59; + i2c.xmit(address, 1, txbuf, 6, rxbuf); + + *x = ((signed int) rxbuf[0] << 8) + rxbuf[1]; + *y = ((signed int) rxbuf[2] << 8) + rxbuf[3]; + *z = ((signed int) rxbuf[4] << 8) + rxbuf[5]; +} + +void MPU9250::getAccel(float *g_x, float *g_y, float *g_z) +{ + int x, y, z; + unsigned char g_factor = 2; + for (unsigned char i = 0; i < accel_fsr; i++) { + g_factor *= 2; + } + + getRawAccel(&x, &y, &z); + + float fsr_factor = g_factor / 32768.; + + *g_x = x * fsr_factor; + *g_y = y * fsr_factor; + *g_z = z * fsr_factor; +} + +void MPU9250::getGyro(float *dps_x, float *dps_y, float *dps_z) +{ + int x, y, z; + unsigned short dps_factor = 250; + for (unsigned char i = 0; i < gyro_fsr; i++) { + dps_factor *= 2; + } + + getRawGyro(&x, &y, &z); + + float fsr_factor = dps_factor / 32768.; + + *dps_x = x * fsr_factor; + *dps_y = y * fsr_factor; + *dps_z = z * fsr_factor; +} + +void MPU9250::getRawMagnet(int *x, int *y, int *z) { txbuf[0] = 0x02; - i2c.xmit(0x0c, 0, txbuf, 8, rxbuf); + i2c.xmit(0x0c, 1, txbuf, 8, rxbuf); if ((rxbuf[0] & 0x01) && !(rxbuf[7] & 0x08)) { *x = ((signed int)rxbuf[2] << 8) + rxbuf[1]; |