diff options
| -rw-r--r-- | libraries/Wire/utility/twi.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/libraries/Wire/utility/twi.c b/libraries/Wire/utility/twi.c index 82a25c0..bfa917a 100644 --- a/libraries/Wire/utility/twi.c +++ b/libraries/Wire/utility/twi.c @@ -135,7 +135,12 @@ uint8_t twi_readFrom(uint8_t address, uint8_t* data, uint8_t length) // initialize buffer iteration vars twi_masterBufferIndex = 0; - twi_masterBufferLength = length; + twi_masterBufferLength = length-1; // This is not intuitive, read on... + // On receive, the previously configured ACK/NACK setting is transmitted in + // response to the received byte before the interrupt is signalled. + // Therefor we must actually set NACK when the _next_ to last byte is + // received, causing that NACK to be sent in response to receiving the last + // expected byte of data. // build sla+w, slave device address + w bit twi_slarw = TW_READ; |