wayne roberts
example of i2c slave device supporting block transfers
Dependencies: lib_i2c_slave_block
Tested on nucleo board as slave. Use with i2c_master_block_example on raspberry pi as master.
Master I2C write will print on serial terminal 115200. User button will raise an irq; the RPi test program will service the interrupt.
See lib_i2c_slave_block for explanation of code.
Diff: main.cpp
- Revision:
- 0:3ccfaf358115
- Child:
- 2:d7e05c75f240
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Fri Jan 18 14:36:09 2019 -0800
@@ -0,0 +1,92 @@
+
+#include <mbed.h>
+#include "smbus.h"
+#include "cmds.h"
+
+#define IRQ_OUT_PIN D6
+
+const int SLAVE_ADDRESS = 0xA0;
+
+RawSerial pc(USBTX, USBRX);
+
+DigitalOut irqOutPin(IRQ_OUT_PIN);
+irq_t irq;
+
+DigitalIn button(USER_BUTTON);
+
+
+void fill_tx_buf(uint8_t cmd)
+{
+ static uint8_t cnt = 0;
+ unsigned i;
+
+ /* answering (master read) request here */
+
+ switch (cmd) {
+ case CMD_TEST3:
+ case CMD_TEST12:
+ case CMD_TEST32:
+ for (i = 0; i < cmd_to_length[cmd]; i++)
+ i2c.tx_buf[i] = i + cnt;
+ cnt++;
+ break;
+ case CMD_IRQ:
+ for (i = 0; i < cmd_to_length[CMD_IRQ]; i++)
+ i2c.tx_buf[i] = irq.buf[i];
+
+ /* interrupt was (is being) read, clear it */
+ irq.fields.flags.button = 0;
+ if (irq.buf[0] == 0)
+ irqOutPin = 0;
+
+ break;
+ }
+}
+
+void service_i2c_write(uint8_t cmd, uint8_t len, const uint8_t* req)
+{
+ uint8_t s8;
+
+ /* taking master write here */
+
+ switch (cmd) {
+ case CMD_TEST3:
+ case CMD_TEST12:
+ case CMD_TEST32:
+ for (s8 = 0; s8 < cmd_to_length[cmd]; s8++)
+ pc.printf("%02x ", req[s8]);
+ pc.printf("\r\n");
+ break;
+ default:
+ pc.printf("??%02x??|\r\n", cmd);
+ break;
+ } // ..switch (cmd)
+}
+
+int main()
+{
+ int res;
+ bool but;
+ uint8_t cnt = 0;
+
+ pc.baud(115200);
+ pc.printf("\r\nreset\r\n");
+
+ res = smbus_init(SLAVE_ADDRESS);
+ pc.printf("%d = smbus_init()\r\n", res);
+
+ but = button.read();
+ while (1) {
+ service_i2c();
+
+ if (but != button.read()) {
+ irq.fields.cnt = cnt++;
+ irq.fields.flags.button = 1;
+ irqOutPin = 1;
+
+ but = button.read();
+ }
+
+ } // ..while (1)
+}
+