Inter-integrated circuit (I
2
C) interface RM0016
294/449 Doc ID 14587 Rev 8
21.7.2 Control register 2 (I2C_CR2)
Address offset: 0x01
Reset value: 0x00
76543210
SWRST
Reserved
POS ACK STOP START
rw rw rw rw rw
Bit 7 SWRST: Software reset
When set, the I2C is at reset state. Before resetting this bit, make sure the I2C lines are released and
the bus is free.
0: I2C Peripheral not at reset state
1: I2C Peripheral at reset state
Note: This bit can be used in case the BUSY bit is set to ‘1’ when no stop condition has been
detected on the bus.
Bits 6::4 Reserved
Bit 3 POS: Acknowledge position (for data reception).
This bit is set and cleared by software and cleared by hardware when PE=0.
0: ACK bit controls the (N)ACK of the current byte being received in the shift register.
1: ACK bit controls the (N)ACK of the next byte which will be received in the shift register.
Note: The POS bit is used when the procedure for reception of 2 bytes (see Method 2: transfer
sequence diagram for master receiver when N=2) is followed. It must be configured before data
reception starts. In this case, to NACK the 2nd byte, the ACK bit must be cleared just after
ADDR is cleared.
Note:
Bit 2 ACK: Acknowledge enable
This bit is set and cleared by software and cleared by hardware when PE=0.
0: No acknowledge returned
1: Acknowledge returned after a byte is received (matched address or data)
Bit 1 STOP: Stop generation
The bit is set and cleared by software, cleared by hardware when a Stop condition is detected, set by
hardware when a timeout error is detected.
– In Master mode:
0: No Stop generation.
1: Stop generation after the current byte transfer or after the current Start condition is sent.
– In Slave mode:
0: No Stop generation.
1: Release the SCL and SDA lines after the current byte transfer.
Bit 0 START: Start generation
This bit is set and cleared by software and cleared by hardware when start is sent or PE=0.
– In Master mode:
0: No Start generation
1: Repeated start generation
– In Slave mode:
0: No Start generation
1: Start generation when the bus is free
To Next Page
Loading...
Need help?
General
