Datasheet

DocID024647 Rev 1 81/138

RM0352 I

C bus interface

137

[20] SMBDEFAULT: SMBus device default address (slave mode)

0: no SMBus device default address

1: SMBus device default address received when ENARP = 1

• Cleared by hardware after a STOP condition or repeated START

condition, or when PE = 0.

[19:9] LENGTH: transfer length. For an MR, WTS operation the LENGTH field

defines the actual size of the subsequent payload, in terms of number of

bytes. For an MW, RFS operation the LENGTH field defines the actual

number of bytes transferred by the master/slave device. For a WTS

operation if the transfer length exceeds 2047 bytes, the operation is stopped

by the slave returning a NACK handshake and the flag OVFL is set. For an

RFS operation if the transfer length exceeds 2047 bytes, the operation

continues normally but the LENGTH field is reset to 0.

[8:7] TYPE: receive type. Valid only for the operation WTS

00: FRAME: the slave has received a normal frame

01: GCALL: the slave has received a general call. If the it I2C_CR:SGCM is

set to 1, the general call is directly executed without software intervention

and only the control code word is reported in the FIFO (LENGTH = 0).

10: HW_GCALL: The slave has received a hardware general call.

11: RESERVED

[6:4] CAUSE: abort cause. This field is valid only when the STATUS field contains

the ABORT tag. Others: RESERVED.

000: NACK_ADDR: the master receives a not-acknowledge after the

transmission of the address. Valid for the operations MW, MR.

001: NACK_DATA: the master receives a not-acknowledge during the data

phase of an MW operation. Valid for the operation MW.

010: ACK_MCODE: the master receives an acknowledge after the

transmission of the master code in Hs mode. Valid for the operations MW,

MR in HS mode.

011: ARB_LOST: the master loses the arbitration during a MW or MR

operation. Valid for the operations MW, MR.

100: BERR_START: the slave restarts, a START condition occurs while the

byte transfer is not terminated.

101: BERR_STOP: the slave resets, a STOP condition while the byte

transfer is not terminated.

110: OVFL: the slave receives a frame related to the WTS operation longer

than the maximum size = 2047 bytes. In this case the slave device returns

a NACK to complete the data transfer. Valid for a WTS operation.