Fujitsu 8FX User Manual

MB95630H Series
528 FUJITSU SEMICONDUCTOR LIMITED MN702-00009-2v0-E
CHAPTER 24 I
2
C BUS INTERFACE
24.8 Notes on Using I
2
C Bus Interface
24.8 Notes on Using I
2
C Bus Interface
This section provides notes on using the I
2
C bus interface.
■ Notes on Using I
2
C Bus Interface
● Notes on setting I
2
C bus interface registers
• Enable the I
2
C bus interface operation (ICCRn:EN) before setting the I
2
C bus control
registers ch. n (IBCR0n and IBCR1n).
• Setting the master/slave select bit (IBCR1n:MSS) to "1" starts data transfer.
● Notes on setting the shift clock frequency
• The shift clock frequency can be calculated by determining the m, n, and DMBP values
using the Fsck equation. See "24.7.6 I
2
C Clock Control Register ch. n (ICCRn)" for details
of the Fsck equation.
• Do not write "1" to the DMBP bit in the ICCRn register if the value of n is 4
(ICCRn:CS[2:0] = 0b000).
● Notes on priority for simultaneous write operations
• Conflict between next byte transfer and stop condition
When writing "0" to IBCR1n:MSS and clearing IBCR1n:INT occur simultaneously, the
MSS bit is given priority and a STOP condition is generated.
• Conflict between next byte transfer and start condition
When writing "1" to IBCR1n:SCC and clearing IBCR1n:INT occur simultaneously, the
SCC bit is given priority and a START condition is generated.
● Notes on setting up using software
• Do not select the repeated START condition (IBCR1n:SCC = 1) or slave mode
(IBCR1n:MSS = 0) simultaneously.
• The I
2
C bus interface cannot return from interrupt processing if an interrupt request enable
bit is enabled (IBCR1n:BEIE = 1 or IBCR1n:INTE = 1) with the interrupt request flag bit
(IBCR1n:BER or IBCR1n:INT) set to "1". Clear the BER bit or the INT bit.
• The following bits are cleared to "0" when the I
2
C bus interface operation is disabled
(ICCRn:EN = 0).
- AACKX, INTS, and WUE bits in the IBCR0n register
- All bits in the IBCR1n register except the BER bit and the BEIE bit
- All bits in the IBSRn register
● Notes on data acknowledgment
In slave mode, a data acknowledge is generated if one of the following conditions is satisfied.
- The received address matches the value in the address register (IAARn) and
IBCR0n:AACKX is "0".
- A general call address (0x00) is received and IBCR1n:GACKE is "1".

Fujitsu 8FX Specifications

General

Brand	Fujitsu
Model	8FX
Category	Computer Hardware
Language	English