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runtime/i2c: more conservative timings

This commit is contained in:
Sebastien Bourdeauducq 2016-03-23 12:54:13 +08:00
parent 2bb4ad189a
commit 799c2c77c4
1 changed files with 4 additions and 1 deletions
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5
artiq/runtime/i2c.c
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@ -139,6 +139,7 @@ int i2c_write(int busno, int b)
for(i=7;i>=0;i--) {
/* Set SCL low and set our bit on SDA */
i2c_scl_o(busno, 0);
i2c_halfperiod(); /* make sure SCL has settled low */
i2c_sda_oe(busno, b & (1 << i) ? 0 : 1);
i2c_halfperiod();
/* Set SCL high ; data is shifted on the rising edge of SCL */
@ -148,8 +149,9 @@ int i2c_write(int busno, int b)
/* Check ack */
/* Set SCL low, then release SDA so that the I2C target can respond */
i2c_scl_o(busno, 0);
i2c_halfperiod();
i2c_halfperiod(); /* make sure SCL has settled low */
i2c_sda_oe(busno, 0);
i2c_halfperiod();
/* Set SCL high and check for ack */
i2c_scl_o(busno, 1);
i2c_halfperiod();
@ -182,6 +184,7 @@ int i2c_read(int busno, int ack)
/* Send ack */
/* Set SCL low and pull SDA low when acking */
i2c_scl_o(busno, 0);
i2c_halfperiod(); /* make sure SCL has settled low */
if(ack)
i2c_sda_oe(busno, 1);
i2c_halfperiod();