ARMmbed
/
mbed-os
mirror of https://github.com/ARMmbed/mbed-os.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

I2C blockread and blockwrite fixed for LPC812 

Quick fix of block read and write. The i2c_start is still wrong: it
should setup the address before initiating a Start condition. Status
read is also wrong in i2c_do_read.
pull/862/head
Willem23 2015-01-24 20:59:01 +01:00
parent ebc51cd52c
commit 3b7d9635b7
1 changed files with 57 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

88
libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC81X/i2c_api.c
View File

@ -86,11 +86,16 @@ inline int i2c_start(i2c_t *obj) {
return status;
}
//Generate Stop condition and wait until bus is Idle
//Will also send NAK for previous RD
inline int i2c_stop(i2c_t *obj) {
int timeout = 0;
obj->i2c->MSTCTL = (1 << 2) | (1 << 0);
while ((obj->i2c->STAT & ((1 << 0) | (7 << 1))) != ((1 << 0) | (0 << 1))) {
obj->i2c->MSTCTL = (1 << 2) | (1 << 0); // STP bit and Continue bit. Sends NAK to complete previous RD
while ((obj->i2c->STAT & ((7 << 1) | (1 << 0))) != ((0 << 1) | (1 << 0))) { //Spin until Ready (b0 == 1)and Status is Idle (b3..b1 == 000)
timeout ++;
if (timeout > 100000) return 1;
}
@ -98,7 +103,6 @@ inline int i2c_stop(i2c_t *obj) {
return 0;
}
static inline int i2c_do_write(i2c_t *obj, int value, uint8_t addr) {
// write the data
I2C_DAT(obj) = value;
@ -145,62 +149,82 @@ void i2c_frequency(i2c_t *obj, int hz) {
// because something is setup wrong (e.g. wiring), and we don't need to programatically
// check for that
//New version WH, Tested OK for Start and Repeated Start
//Old version was Wrong: Calls i2c_start without setting address, i2c_do_read continues before checking status, status check for wrong value
int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) {
int count, status;
i2c_start(obj);
status = i2c_do_write(obj, (address | 0x01), 1);
if (status != 0x01) {
//Store the address+RD and then generate STA
I2C_DAT(obj) = address | 0x01;
i2c_start(obj);
// Wait for completion of STA and Sending of SlaveAddress+RD and first Read byte
i2c_wait_SI(obj);
status = i2c_status(obj);
if (status == 0x03) { // NAK on SlaveAddress
i2c_stop(obj);
return I2C_ERROR_NO_SLAVE;
}
// Read in all except last byte
for (count = 0; count < (length - 1); count++) {
int value = i2c_do_read(obj, 0);
status = i2c_status(obj);
if (status != 0x00) {
i2c_stop(obj);
return count;
}
data[count] = (char) value;
}
// read in last byte
int value = i2c_do_read(obj, 1);
status = i2c_status(obj);
if (status != 0x01) {
for (count = 0; count < (length-1); count++) {
// Wait for it to arrive, note that first byte read after address+RD is already waiting
i2c_wait_SI(obj);
status = i2c_status(obj);
if (status != 0x01) { // RX RDY
i2c_stop(obj);
return length - 1;
return count;
}
data[count] = I2C_DAT(obj) & 0xFF; // Store read byte
obj->i2c->MSTCTL = (1 << 0); // Send ACK and Continue to read
}
data[count] = (char) value;
// Read final byte
// Wait for it to arrive
i2c_wait_SI(obj);
status = i2c_status(obj);
if (status != 0x01) { // RX RDY
i2c_stop(obj);
return count;
}
data[count] = I2C_DAT(obj) & 0xFF; // Store final read byte
// If not repeated start, send stop.
if (stop) {
i2c_stop(obj);
i2c_stop(obj); // Also sends NAK for last read byte
} else {
repeated_start = 1;
}
return length;
}
//New version WH, Tested OK for Start and Repeated Start
//Old version was Wrong: Calls i2c_start without setting address first
int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) {
int i, status;
//Store the address+/WR and then generate STA
I2C_DAT(obj) = address & 0xFE;
i2c_start(obj);
status = i2c_do_write(obj, (address & 0xFE), 1);
if (status != 0x02) {
// Wait for completion of STA and Sending of SlaveAddress+/WR
i2c_wait_SI(obj);
status = i2c_status(obj);
if (status == 0x03) { // NAK SlaveAddress
i2c_stop(obj);
return I2C_ERROR_NO_SLAVE;
}
//Write all bytes
for (i=0; i<length; i++) {
status = i2c_do_write(obj, data[i], 0);
if (status != 0x02) {
if (status != 0x02) { // TX RDY. Handles a Slave NAK on datawrite
i2c_stop(obj);
return i;
}
@ -216,6 +240,8 @@ int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) {
return length;
}
void i2c_reset(i2c_t *obj) {
i2c_stop(obj);
}