Fujitsu FR81S User Manual
CHAPTER 40: MULTI-FUNCTION SERIAL INTERFACE
4. Registers
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : MULTI-FUNCTION SERIAL INTERFACE
FUJITSU SEMICONDUCTOR CONFIDENTIAL
119
Bit name
Function
bit1 BER:
Bus error flag
bit
This bit indicates that an error has been detected on I
2
C bus.
BER bit set conditions:
(1) While the first byte* transferring, detects a start condition or a stop condition.
(2) For the second byte or later, detects a (repeat) start condition or a stop condition at the
2-9th (acknowledge) bit of data.
BER bit reset conditions:
(1) Write "0" to the INT bit when BER = 1
(2) I
2
C interface disable (ISMK:EN bit="0")
*: The first byte: indicates data after the (repeat) start condition.
"0": No error
"1": Error detected
Note:
Check this flag when interrupt flag (INT bit) turns "1". If it is "1", as normal send/receive
operations could not be performed, send the data again.
bit0
INT:
Interrupt flag
bit
Sets this flag to "1" when in master or slave mode, after 8 or 9 bits (ACK) of the data
transmission/reception, or upon a bus error. When the INT bit is "1", state of SCL turns to
"L" and when "0", exits from "L" state except for bus errors.
INT bit set conditions:
<8th bit>
<It is unrelated to the DMA mode >
(1) When a reserved address is detected in the first byte
(2) When WSEL is "1" and arbitration lost is detected in the second byte or later
< When DMA mode is disabled (SSR:DMA=0)>
(1) When DMA mode is disabled (SSR:DMA=0), WSEL is "1" and the SSR:TDRE bit is
"1" in the second byte or later in master operation
(2) When DMA mode is disabled (SSR:DMA=0), WSEL is "1" and reception FIFO is
disabled, the SSR:TDRE bit is "1" in the second byte or later in slave operation
(3) When DMA mode is disabled (SSR:DMA=0), WSEL is "1" and the SSR:TDRE bit is
"1" in the second byte or later in slave transmission
(4) When DMA mode is disabled (SSR:DMA=0), WSEL is "1" and reception FIFO
disabled in the slave reception
< When DMA mode is enabled (SSR:DMA=1)>
(1) When DMA mode is enabled (SSR:DMA=1), WSEL is "1" and the SSR:TBI bit is "1"
and "1" is written to the INT bit in the second byte or later in master operation
<9th bit>
< It is unrelated to the DMA mode >
(1) When arbitration lost is detected in the first byte
(2) When NACK received except for stop condition output setting (write "0" to MSS bit
in master operation)
(3) When WSEL is "0" and arbitration lost is detected in the second byte or later
(4) In the first byte, no reserved address is detected in the receiving direction in master or
slave mode (IBSR:TRX=0) and there are reception FIFO data at reception FIFO
enable state
< When DMA mode is disabled (SSR:DMA=0)>
(1) When DMA mode is disabled (SSR:DMA=0), in the first byte, no reserved address is
detected and the SSR:TDRE bit is "1" in the transmission direction in master or slave
mode (IBSR:TRX=1)
(2) When DMA mode is disabled (SSR:DMA=0), the SSR:TDRE bit is "1" when you
prohibit reception FIFO without detecting the reservation address in the first byte in
the receiving direction in master or slave mode (IBSR:TRX=0)
(3) When DMA mode is disabled (SSR:DMA=0), WSEL is "0" and the SSR:TDRE bit is
"1" in the second byte or later in master operation
MB91520 Series
MN705-00010-1v0-E
1432