From c037f0676fc079db1643b2cc400f387ce39ed30c Mon Sep 17 00:00:00 2001 From: Lars-Dominik Braun Date: Tue, 4 Feb 2014 11:08:41 +0100 Subject: Write with interrupt + multi-read --- main.c | 233 +++++++++++++++++++++++++++++++++++++++++------------------------ 1 file changed, 148 insertions(+), 85 deletions(-) (limited to 'main.c') diff --git a/main.c b/main.c index f83d090..4858a5e 100644 --- a/main.c +++ b/main.c @@ -1,12 +1,12 @@ -/* cpu freq */ +/* cpu runs at 1mhz */ #define F_CPU 1000000 #include +#include #include #include #include - -/* cpu runs at 1mhz */ +#include /* i2c device addresses */ #define L3GD20 0b11010100 @@ -16,29 +16,83 @@ #define LIS302DL_WHOAMI 0xf #define LIS302DL_CTRLREG1 0x20 -void twStart () { - /* disable stop, reset twint, enable start, enable i2c */ - TWCR = (TWCR & ~(1 << TWSTO)) | (1 << TWINT) | (1 << TWSTA) | (1 << TWEN); +typedef enum { + TWST_WAIT = 0, + TWST_OK = 1, + TWST_ERR = 2, +} twStatus; + +typedef struct { + uint8_t address; + uint8_t subaddress; + uint8_t data; + uint8_t step; + twStatus status; +} twReq; + +volatile twReq twr; + +void twStartRaw () { + /* disable stop, enable interrupt, reset twint, enable start, enable i2c */ + TWCR = (TWCR & ~(1 << TWSTO)) | (1 << TWIE) | (1 << TWINT) | (1 << TWSTA) | (1 << TWEN); +} + +void twStopRaw () { + /* disable start, enable interrupt, reset twint, enable stop, enable i2c */ + TWCR = (TWCR & ~(1 << TWSTA)) | (1 << TWIE) | (1 << TWINT) | (1 << TWSTO) | (1 << TWEN); } -void twStop () { - /* disable start, reset twint, enable stop, enable i2c */ - TWCR = (TWCR & ~(1 << TWSTA)) | (1 << TWINT) | (1 << TWSTO) | (1 << TWEN); +void twFlushRaw () { + /* disable start/stop, enable interrupt, reset twint, enable i2c */ + TWCR = (TWCR & ~((1 << TWSTA) | (1 << TWSTO) | (1 << TWEA))) | (1 << TWIE) | (1 << TWINT) | (1 << TWEN); } -void twFlush () { - /* disable start/stop, reset twint, enable i2c */ - TWCR = (TWCR & ~((1 << TWSTA) | (1 << TWSTO))) | (1 << TWINT) | (1 << TWEN); +/* flush and send master ack */ +void twFlushContRaw () { + /* disable start/stop, enable interrupt, reset twint, enable i2c, send master ack */ + TWCR = (TWCR & ~((1 << TWSTA) | (1 << TWSTO))) | (1 << TWIE) | (1 << TWINT) | (1 << TWEN) | (1 << TWEA); } -void twWait () { +void twWaitRaw () { while (!(TWCR & (1 << TWINT))); } +bool twWriteRaw (uint8_t data) { + TWDR = data; + if (TWCR & (1 << TWWC)) { + printf("write collision\n"); + return false; + } else { + return true; + } +} + void twInit () { /* set scl to 3.6 kHz (at 1Mhz CPU speed)*/ TWBR = 2; TWSR |= 0x3; /* set prescaler to 64 */ + + twr.status = TWST_ERR; +} + +/* high-level write + */ +static bool twWrite (uint8_t address, uint8_t subaddress, uint8_t data) { + /* do not start if request is pending */ + if (twr.status == TWST_WAIT) { + return false; + } + + twr.address = address | TW_WRITE; + twr.subaddress = subaddress; + twr.data = data; + twr.step = 0; + twr.status = TWST_WAIT; + /* wait for stop finish */ + while (TW_STATUS != 0xf8); + twStartRaw (); + + return true; } void ledInit () { @@ -99,6 +153,48 @@ void cpuInit () { CLKPR = 0b00000011; } +ISR(TWI_vect) { + printf ("interupt hit with step %i\n", twr.step); + switch (twr.step) { + case 0: + if (TW_STATUS == TW_START) { + twWriteRaw (twr.address); + twFlushRaw (); + } else { + twr.status = TWST_ERR; + } + break; + + case 1: + if (TW_STATUS == TW_MT_SLA_ACK) { + twWriteRaw (twr.subaddress); + twFlushRaw (); + } else { + twr.status = TWST_ERR; + } + break; + + case 2: + if (TW_STATUS == TW_MT_DATA_ACK) { + twWriteRaw (twr.data); + twFlushRaw (); + } else { + twr.status = TWST_ERR; + } + break; + + case 3: + if (TW_STATUS == TW_MT_DATA_ACK) { + twStopRaw (); + twr.status = TWST_OK; + } else { + twr.status = TWST_ERR; + } + break; + } + ++twr.step; +} + int main(void) { cpuInit (); ledInit (); @@ -110,62 +206,19 @@ int main(void) { printf ("initialization done\n"); + sei (); /* disable power-down-mode */ - twStart (); - twWait (); - unsigned char status = 0x0; - - /* check status code */ - if ((status = TW_STATUS) == TW_START) { - /* write device address and write bit */ - TWDR = LIS302DL | TW_WRITE; - if (TWCR & (1 << TWWC)) { - printf("write collision\n"); - } - twFlush (); - twWait (); - if ((status = TW_STATUS) == TW_MT_SLA_ACK) { - } else { - printf ("fail with code %x\n", status); - } - - /* write subaddress (actually i2c data) */ - TWDR = LIS302DL_CTRLREG1; - if (TWCR & (1 << TWWC)) { - printf("write collision\n"); - } - twFlush (); - twWait (); - if ((status = TW_STATUS) == TW_MT_DATA_ACK) { - } else { - printf ("fail with code %x\n", status); - } - - /* write actual data */ - TWDR = 0b01000111; - if (TWCR & (1 << TWWC)) { - printf("write collision\n"); - } - twFlush (); - twWait (); - if ((status = TW_STATUS) == TW_MT_DATA_ACK) { - } else { - printf ("fail with code %x\n", status); - } - - twStop (); - _delay_ms (100); - } else { - printf ("write: start failed\n"); + if (!twWrite (LIS302DL, LIS302DL_CTRLREG1, 0b01000111)) { + printf ("cannot start write\n"); } + while (twr.status == TWST_WAIT); + printf ("final twi status was %i\n", twr.status); + cli (); while (1) { - unsigned char reg[] = {0x29, 0x2b, 0x2d}; signed char val[6]; - //unsigned char reg[] = {0xf, 0x20, 0x21, 0x22, 0x23, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2d, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f}; - for (unsigned char i = 0; i < sizeof (reg)/sizeof(*reg); i++) { - twStart (); - twWait (); + twStartRaw (); + twWaitRaw (); unsigned char status = 0x0; /* check status code */ @@ -176,28 +229,28 @@ int main(void) { if (TWCR & (1 << TWWC)) { printf("write collision\n"); } - twFlush (); - twWait (); + twFlushRaw (); + twWaitRaw (); if ((status = TW_STATUS) == TW_MT_SLA_ACK) { } else { printf ("fail with code %x\n", status); } - /* write subaddress (actually i2c data) */ - TWDR = reg[i]; + /* auto increment + subaddress */ + TWDR = (1 << 7) | 0x28; if (TWCR & (1 << TWWC)) { printf("write collision\n"); } - twFlush (); - twWait (); + twFlushRaw (); + twWaitRaw (); if ((status = TW_STATUS) == TW_MT_DATA_ACK) { } else { printf ("fail with code %x\n", status); } /* repeated start */ - twStart (); - twWait (); + twStartRaw (); + twWaitRaw (); if ((status = TW_STATUS) == TW_REP_START) { } else { printf ("fail with code %x\n", status); @@ -208,24 +261,35 @@ int main(void) { if (TWCR & (1 << TWWC)) { printf("write collision\n"); } - twFlush (); - twWait (); + twFlushRaw (); + twWaitRaw (); if ((status = TW_STATUS) == TW_MR_SLA_ACK) { } else { printf ("fail with code %x\n", status); } - /* clear twint and wait for response */ - twFlush (); - twWait (); - if ((status = TW_STATUS) == TW_MR_DATA_NACK) { - } else { - printf ("fail with code %x\n", status); + for (uint8_t i = 0; i < 6; i++) { + /* clear twint and wait for response */ + if (i < 5) { + twFlushContRaw (); + twWaitRaw (); + if ((status = TW_STATUS) == TW_MR_DATA_ACK) { + } else { + printf ("fail with code %x in val %i\n", status, i); + } + } else { + twFlushRaw (); + twWaitRaw (); + if ((status = TW_STATUS) == TW_MR_DATA_NACK) { + } else { + printf ("fail with code %x in val %i\n", status, i); + } + } + unsigned char ret = TWDR; + val[i] = ret; } - unsigned char ret = TWDR; - val[i] = ret; - twStop (); + twStopRaw (); /* there is no way to tell whether stop has been sent or not, just wait */ _delay_ms (10); @@ -233,9 +297,8 @@ int main(void) { printf ("fail with code %x\n", status); _delay_ms (1000); } - } //printf ("%i/%i/%i\n", (val[1] << 8) | val[0], (val[3] << 8) | val[2], (val[5] << 8) | val[4]); - printf ("%i/%i/%i\n", val[0], val[1], val[2]); + printf ("%i/%i/%i\n", val[1], val[3], val[5]); } while (1); -- cgit v1.2.3