/* (CC-BY-NC-SA) ROBIN KRENS - ROBIN @ ROBINKRENS.NL
*
* $LOG$
- * 2019/7/25 - ROBIN KRENS
+ * 2019/8/11 - ROBIN KRENS
* Initial version
*
* $DESCRIPTION$
+ * Driver for AT24C256 EEPROM for STM32 based boards. Communication protocol is I2C
+ * Maximum write in limited to 64 bytes. Reading bytes is unlimited, but memory should
+ * be allocated accordingly.
+ *
+ * I2C protocol : (W)rite or (R)ead
+ * MCU is in master mode: either as transmitter or receiver
+ * | P | DEVICEADDR + R/W bit | ACK | ADDR_PART1 | ACK | ADDR_PART2 | (d+a*n) | (N)ACK | S
+ * Sending data: wait for ACK from EEPROM
+ * Receiving data: send (n)ACK to EEPROM after receiving data
+ *
+ * STM32F1 microcontrollers do not provide the ability to pull-up SDA and SCL lines. Their
+ * GPIOs must be configured as open-drain. So, you have to add two additional resistors to
+ * pull-up I2C lines. Something between 4K and 10K is a proven value.
*
* */
#include <lib/regfunc.h>
#include <lib/string.h>
-#include <lib/stdio.h>
#include <lib/tinyprintf.h>
#include <drivers/at24c.h>
#define TIMEOUT 5000
+#define READ_CMD 0xA1
+#define WRITE_CMD 0xA0
+#define PAGE 64 /* Bytes that can be written continiously */
+#define BUFFER 64 /* Reading buffer */
-#define READ_CMD 0xA1
-#define WRITE_CMD 0xA0
-#define PAGE 64 /* Bytes that can be written continiously */
-#define BUFFER 4 /* */
-
-/* STM32F1 microcontrollers do not provide the ability to pull-up SDA and SCL lines. Their
-GPIOs must be configured as open-drain. So, you have to add two additional resistors to
-pull-up I2C lines. Something between 4K and 10K is a proven value.
-*/
static char eeprombuf[BUFFER];
-void * cap_handler() {
-
- printf("a!");
-}
-
-void at24c_init() {
+void eeprom_at24c_init() {
- /* Program the peripheral input clock in I2C_CR2 Register
- * in order to generate correct timings. Configure the clock control registers CCR
- Configure the rise time register TRIS Program the I2C_CR1 register to enable the peripheral Enable GPIOB6 and B7*/
+ /* Program the peripheral input clock generate correct timings.
+ * Configure the clock control registers CCR
+ * Configure the rise time register TRIS
+ * Program the I2C_CR1 register to enable the peripheral
+ * Enable GPIOB6 and B7*/
- rsetbit(RCC_APB1ENR, 21);
- rsetbit(RCC_APB2ENR, 3);
- rwrite(GPIOB_CRL, 0xEE444444);
+ rsetbit(RCC_APB1ENR, 21); // enable GPIOB
+ rsetbit(RCC_APB2ENR, 3); // enable I2C
+ rwrite(GPIOB_CRL, 0xEE444444); // open-drain
rsetbitsfrom(I2C_CR2, 0, 0x2); // 2 MHz
rwrite(I2C_TRISE, 0x3); // MAX = 1000ns, TPCLK1 = 500ns (+1)
- rwrite(I2C_CCR, 0x000A); // standard modeļ¼ output 100 kHz (100hz* / perip)
- rsetbit(I2C_CR1, 10); // send ack if Master receives data
+ rwrite(I2C_CCR, 0x000A); // standard mode
rsetbit(I2C_CR2, 10); // buffer interrupt
rsetbit(I2C_CR1, 0); // enable
}
-static void start_condition() {
- rsetbit(I2C_CR1, 8); //start
-}
-
-static void stop_condition() {
- rsetbit(I2C_CR1, 9); //stop
-}
-
-static int ack_recv() {
- int cnt = 0;
- while(!(*I2C_SR1 & 0x2)) {
- cnt++;
- if (cnt > TIMEOUT)
- return 0;
- }
-
- int a = *I2C_SR2;
- return 1;
-}
-
-static int buf_empty() {
- int cnt = 0;
- while(!(*I2C_SR1 & 0x80)) {
- cnt++;
- if (cnt > TIMEOUT)
- return 0;
- }
- return 1;
-}
-
-// TODO: interrupt base, so it doesn't block
-static void data_recv() {
- while(!(*I2C_SR1 & 0x40)) {
- }
-}
-
-static void late_recv() {
- while(!(*I2C_SR1 & 0x4)) {
- }
-}
-
-// TODO: polling
-static int delay() {
-
- int a = 0;
- for (int i = 0; i < 0xFFFF; i++)
- a++;
-}
-
+/* Writes data to the EEPROM starting at address addr. Size can not
+ * be more than one PAGE (64 bytes) */
int eeprom_write(uint16_t addr, char * data, size_t size) {
if(size > PAGE) {
- printf("Maximum writable page size: %d\n", PAGE);
+ printf("Error: Maximum writable page size: %d\n", PAGE);
return -1;
}
start_condition();
rwrite(I2C_DR, WRITE_CMD);
- if(!ack_recv()) {
- printf("Can't reach device");
+ if(!ack_recv())
return -1;
- }
+
rwrite(I2C_DR, hi_lo[0]); // higher part of address
- if(!buf_empty()) {
- printf("Can't address location");
+ if(!buf_empty())
return -1;
- }
+
rwrite(I2C_DR,hi_lo[1]); // lower part of address
- if(!buf_empty()) {
- printf("Can't address location");
+ if(!buf_empty())
return -1;
- }
+
for (int i = 0; i < size; i++) {
rwrite(I2C_DR, *data++);
- if(!buf_empty()) {
- printf("Write error");
+ if(!buf_empty())
return -1;
- }
+
}
stop_condition();
+ delay(); // wait for write action to finish
+ return 0;
+}
+
+/* Erase (write all 0xFF) data on EEPROM
+ * Maximum hardware allowed sequential writes of 64 bytes */
+int eeprom_erase() {
+
+ uint16_t cur_addr = 0x0000;
+
+ for (int i = 0; i < 512; i++) {
+
+ printf("Writing at address: %#x (64 bytes) ", cur_addr);
+ uint8_t hi_lo[] = { (uint8_t)(cur_addr >> 8), (uint8_t)cur_addr };
+
+ start_condition();
+ rwrite(I2C_DR, WRITE_CMD);
+ if(!ack_recv())
+ return -1;
+
+
+ rwrite(I2C_DR, hi_lo[0]); // higher part of address
+ if(!buf_empty())
+ return -1;
+
+ rwrite(I2C_DR,hi_lo[1]); // lower part of address
+ if(!buf_empty())
+ return -1;
+
+
+ for (int i = 0; i < PAGE; i++) {
+ rwrite(I2C_DR, 0xFF); // write all ones
+ if(!buf_empty())
+ return -1;
+
+ }
+ stop_condition();
+ printf("[COMPLETE]\n");
+ cur_addr += 0x40; // 64 bytes; next PAGE
+ delay(); // wait for write to finish
+ }
return 0;
}
-/* Random access read based on dummy write */
-int eeprom_read(uint16_t addr, int num) {
- printf("ENTERING");
+/* Random access read of num bytes
+ * Initialize dummy write first to set correct address location
+ * The read function differentiate between num = 1 num = 2 and num > 3
+ * Data is saved to rvalues */
+int eeprom_read(uint16_t addr, int num, char * rvalues) {
+
uint8_t hi_lo[] = { (uint8_t)(addr >> 8), (uint8_t)addr };
/* Dummy write to set address */
start_condition();
rwrite(I2C_DR, WRITE_CMD);
- if(!ack_recv()) {
- printf("Can't reach device");
+ if(!ack_recv())
return -1;
- }
rwrite(I2C_DR, hi_lo[0]); // higher part of address
- if(!buf_empty()) {
- printf("Can't address location");
+ if(!buf_empty())
return -1;
- }
+
rwrite(I2C_DR,hi_lo[1]); // lower part of address
- if(!buf_empty()) {
- printf("Can't address location");
+ if(!buf_empty())
return -1;
- }
+
stop_condition();
- delay(); // NEEDED?
+ delay(); // wait form EEPROM
+
+ switch(num) {
+ case 1:
+ start_condition(); // restart condition
+ rwrite(I2C_DR, READ_CMD); // read? to address CMD
+ if(!ack_recv())
+ return -1;
+ stop_condition();
+
+ if(!data_recv())
+ return -1;
+
+ rvalues[0] = (char) *I2C_DR;
+ rvalues[1] = '\0';
+ break;
+ case 2:
+
+ rsetbit(I2C_CR1, 10); // set ACK
+ rsetbit(I2C_CR1, 11); // set POS
+ start_condition(); // restart condition
+ rwrite(I2C_DR, READ_CMD); // read to address CMD
+ if(!ack_recv())
+ return -1;
+ rclrbit(I2C_CR1, 10); // clear ACK
+ if(!late_recv())
+ return -1;
+
+ stop_condition();
+
+ rvalues[0] = (char) *I2C_DR;
+ rvalues[1] = (char) *I2C_DR;
+ rvalues[2] = '\0';
+ break;
+
+ default:
+ rsetbit(I2C_CR1, 10); // set ACK
+ start_condition(); // restart condition
+ rwrite(I2C_DR, READ_CMD); // read to address CMD
+ if(!ack_recv())
+ return -1;
+
+ for(int i = 0; i < num-3; i++) {
+ if(!data_recv())
+ return -1;
+ rvalues[i] = (char) *I2C_DR;
+ }
+
+ if(!late_recv())
+ return -1;
+
+ rclrbit(I2C_CR1, 10);
+ rvalues[num-3] = *I2C_DR;
+ stop_condition();
+ rvalues[num-2] = *I2C_DR;
+ if(!data_recv())
+ return -1;
+
+ rvalues[num-1] = *I2C_DR;
+ rvalues[num] = '\0';
+ }
+ return 0;
- if (num == 1) {
- start_condition(); // restart condition
- rwrite(I2C_DR, READ_CMD); // read? to address CMD
- if(!ack_recv()) {
- printf("Can't initiate read");
- return -1;
- }
- stop_condition();
- data_recv();
- char c = (char) *I2C_DR;
- printf("DATA: %c\n", c);
- }
+}
- else if (num == 2) {
- rsetbit(I2C_CR1, 10); // set ACK
- rsetbit(I2C_CR1, 11); // set POS
- start_condition(); // restart condition
- rwrite(I2C_DR, READ_CMD); // read to address CMD
- if(!ack_recv()) {
- printf("Can't initiate read");
- return -1;
- }
- rclrbit(I2C_CR1, 10); // clear ACK
- late_recv();
- stop_condition();
- char c = (char) *I2C_DR;
- char c2 = (char) *I2C_DR;
- printf("DATA: %c,%c\n", c, c2);
- }
+/* Dump all data on EEPROM to std out */
+int eeprom_dump() {
- else if (num > 2) {
- rsetbit(I2C_CR1, 10); // set ACK
- start_condition(); // restart condition
- rwrite(I2C_DR, READ_CMD); // read to address CMD
- if(!ack_recv()) {
- printf("Can't initiate read");
+ uint16_t curr_addr = 0x0000;
+
+ for (int i = 0; i < 512; i++) {
+
+ if(eeprom_read(curr_addr, 64, eeprombuf) == -1) {
+ printf("Error: Can't (continue) dump");
return -1;
- }
- for(int i = 0; i < num-3; i++) {
- data_recv();
- eeprombuf[i] = (char) *I2C_DR;
}
- late_recv();
- rclrbit(I2C_CR1, 10);
- eeprombuf[num-3] = *I2C_DR;
- stop_condition();
- eeprombuf[num-2] = *I2C_DR;
- data_recv();
- eeprombuf[num-1] = *I2C_DR;
- eeprombuf[num] = '\0';
- printf("DATA: %s\n", eeprombuf);
+ printf("%#x:\n", curr_addr);
+ for (int i = 0; i < strlen(eeprombuf); i++) {
+ printf("%x ", eeprombuf[i]);
+ if (((i % 16) == 0) && (i != 0))
+ printf("\n");
+ }
+ printf("\n");
+ curr_addr += 0x40; // 64 bytes
}
+ return 0;
+}
+/* HELPER SUBROUTINES */
-//W rsetbit(I2C_CR1, 10); // send ack if Master receives data
-//W// data_recv();
-//W// char c = *I2C_DR;
-//W// printf("%d:%p\n", addr, c);
-//W for (int i = 0; i < BUFFER ; i++ ) {
-//W data_recv();
-//W buf[i] = (char) *I2C_DR;
-//W }
-//W
-//W printf("%p, %p, %p, %p\n", *I2C_SR1, *I2C_SR2, *I2C_DR, *I2C_CR1);
-// printf("DATA: %s\n", buf);
-
+static void start_condition() {
+ rsetbit(I2C_CR1, 8); //start bit
}
-void at24c_run() {
-
-// char * gd = "abcd";
-// eeprom_write(0x0000, gd, strlen(gd));
+static void stop_condition() {
+ rsetbit(I2C_CR1, 9); //stop bit
+}
-// delay();
-// char * global_data = "abcdefghijklmnop";
+/* Initial ACK received after address lookup
+ * read registers clear ADDR bit */
+static int ack_recv() {
+ int cnt = 0;
+ while(!(*I2C_SR1 & 0x2)) {
+ cnt++;
+ if (cnt > TIMEOUT) {
+ printf("Error: Can't reach device\n");
+ return 0;
+ }
+ }
+ int a = *I2C_SR2;
+ return 1;
+}
-// eeprom_write(0x0080, global_data, strlen(global_data));
-
-// delay();
-
-// for (int i = 0; i < 0xFFFF; i++) {
-// eeprom_read(i);
-// delay();
-// }
-
- //delay();
-
-// delay();
-// eeprom_read(0x0000, 1);
-// delay();
-// eeprom_read(0x0000, 2);
- delay();
- eeprom_read(0x0000, 4);
- delay();
-
-//W uint32_t statusr;
-//W
-//W start_condition();
-//W rwrite(I2C_DR, WRITE_CMD); // write to address CMD
-//W if(!ack_recv())
-//W cputs("CAN'T REACH DEVICE");
-//W
-//W rwrite(I2C_DR, 0x00);
-//W if(!buf_empty())
-//W cputs("FAIL");
-//W rwrite(I2C_DR, 0x03);
-//W if(!buf_empty())
-//W cputs("FAIL");
-//W //rwrite(I2C_DR, 0x61);
-//W //if(!buf_empty())
-//W // cputs("FAIL");
-//W
-//W //statusr = *I2C_SR1;
-//W //statusr = *I2C_SR2;
-//W stop_condition();
-
-// start_condition();
-// rwrite(I2C_DR, 0xA0); // dummy write
-// if(!ack_recv())
-// cputs("CAN'T REACH DEVICE");
-//
-// rwrite(I2C_DR, 0x00);
-// if(!buf_empty())
-// cputs("FAIL");
-// rwrite(I2C_DR, 0x00);
-// if(!buf_empty())
-// cputs("FAIL");
-//
-//W delay();
-//W
-//W start_condition(); // restart condition
-//W rwrite(I2C_DR, 0xA1); // read? to address CMD
-//W if(!ack_recv())
-//W cputs("COULDN'T START READ CMD");
-//W
-//W
-//W data_recv();
-//W //cputs("NO RESPONSE");
-//W
-//W char a = (char) *I2C_DR;
-//W printf("DATA %c\n", a);
-//W
-//W stop_condition();
- //delay();
-
- //start_condition();
- //statusr = *I2C_SR1; // clear start_signal
- //regw_u32(I2C_DR, 0xC1, 0, OWRITE);
- //if(!ack_recv())
- // cputs("TIMEOUT2!");
- //statusr = *I2C_SR1;
- //statusr = *I2C_SR2;
- //regw_u32(I2C_DR, 0x7D, 0, OWRITE);
- //if(!buf_empty())
- // cputs("TIMEOUT3!");
- //stop_condition();
-
-/* delay();
+/* Check send buffer
+ * Note: BLOCKING function */
+static int buf_empty() {
+ int cnt = 0;
+ while(!(*I2C_SR1 & 0x80)) {
+ cnt++;
+ if (cnt > TIMEOUT) {
+ printf("Error: Can't send data\n");
+ return 0;
+ }
+ }
+ return 1;
+}
- start_condition();
- statusr = *I2C_SR1;
- regw_u32(I2C_DR, DISPLAY_ON, 0, OWRITE);
- if(!ack_recv())
- cputs("TIMEOUT4!");
- stop_condition(); */
+/* Check data receive buffer
+ * Note: BLOCKING function */
+static int data_recv() {
+ int cnt = 0;
+ while(!(*I2C_SR1 & 0x40)) {
+ cnt++;
+ if (cnt > TIMEOUT) {
+ printf("Error: Timeout receiving data\n");
+ return 0;
+ }
+ }
+ return 1;
+}
+/* Similar as above, waits for two packages to be received
+ * one in DR and one in the shadow register */
+static int late_recv() {
+ int cnt = 0;
+ while(!(*I2C_SR1 & 0x4)) {
+ cnt++;
+ if (cnt > TIMEOUT) {
+ printf("Error: Timeout receiving data\n");
+ return 0;
+ }
+ }
+ return 1;
- /* regw_u32(I2C_CR1, 0x1, 8, SETBIT); //start
- uint32_t read_status = *I2C_SR1;
- regw_u32(I2C_DR, 0x40, 0, OWRITE); // write to address CMD
- read_status = *I2C_SR1;
- read_status = *I2C_SR2;
- regw_u32(I2C_CR1, 0x1, 9, SETBIT); //stop
- read_status = *I2C_SR1;
+}
- regw_u32(I2C_CR1, 0x1, 8, SETBIT); //start
- read_status = *I2C_SR1;
- regw_u32(I2C_DR, 0xC1, 0, OWRITE); // segment address
- read_status = *I2C_SR1;
- read_status = *I2C_SR2;
- regw_u32(I2C_DR, 0x7D, 0, OWRITE); // write a six
+/* Write delay form EEPROM chip */
+static int delay() {
+ int a = 0;
+ for (int i = 0; i < 0xFFFF; i++)
+ a++;
+}
- regw_u32(I2C_CR1, 0x1, 9, SETBIT); //stop
- read_status = *I2C_SR1;
- regw_u32(I2C_CR1, 0x1, 8, SETBIT); //start
- read_status = *I2C_SR1;
+int eeprom_test() {
+ char * gd = "Testing the EEPROM chip AT24C256 write and read function";
+ eeprom_write(0x1000, gd, strlen(gd));
+
+ uint16_t curr_addr = 0x1000;
- regw_u32(I2C_DR, DISPLAY_ON, 0, OWRITE);
- read_status = *I2C_SR1;
- regw_u32(I2C_CR1, 0x1, 9, SETBIT); //stop */
+ for (int i = 0; i < 4; i++) {
+ if(eeprom_read(curr_addr, 16, eeprombuf) == -1) {
+ printf("Can't (continue) dump");
+ return -1;
+ }
+ printf("%#x: ", curr_addr);
+ for (int i = 0; i < strlen(eeprombuf); i++) {
+ printf("%x ", eeprombuf[i]);
+ }
+ printf("\n");
+ curr_addr += 0x10; // 16 bytes
+ }
}
-
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