IDT 89HPES12T3G2, Preliminary User'S Manual

Page: 134 / 146

IDT Configuration Registers
PES12T3G2 User Manual 8 - 58 January 28, 2013
Notes
SMBUSCTL - SMBus Control (0x428)
EEPROMINTF - Serial EEPROM Interface (0x42C)
Bit
Field
Field
Name
Type Default
Value
Description
15:0 MSMBCP RW HWINIT
Sticky
Master SMBus Clock Prescalar. This field contains a clock pres-
calar value used during master SMBus transactions. The prescalar
clock period is equal to 32 ns multiplied by the value in this field.
When the field is cleared to zero or one, the clock is stopped.
The initial value of this field is 0x0139 when the master SMBus is
configured to operate in slow mode (i.e., 100 KHz) in the boot con-
figuration and to 0x0053
1
when it is configured to operate in fast
mode (i.e., 400 KHz).
1.
The MSMBCLK low minimum pulse width is equal to half the period programmed in this field. The value of 0x53, which corre-
sponds to ~373 KHz, allows the min low pulse width to be satisfied. In systems where this timing parameter is not critical, the op-
erating frequency may be increased.
16 MSMBIOM RW 0x0
Sticky
Master SMBus Ignore Other Masters. When this bit is set, the
master SMBus proceeds with transactions regardless of whether it
won or lost arbitration.
17 ICHECK-
SUM
RW 0x0
Sticky
Ignore Checksum Errors. When this bit is set, serial EEPROM
initialization checksum errors are ignored (i.e., the checksum
always passes).
21:18 Reserved RO 0x0 Reserved field.
22 SMBDTO RW 0x0 SMBus Disable Time-out. When this bit is set, SMBus time-outs
are disabled on the master and slave SMBuses.
31:23 Reserved RO 0x0 Reserved field.
Bit
Field
Field
Name
Type Default
Value
Description
15:0 ADDR RW 0x0 EEPROM Address. This field contains the byte address in the
Serial EEPROM to be read or written.
23:16 DATA RW 0x0 EEPROM Data. A write to this field will initiates a serial EEPROM
read or write operation, as selected by the OP field, to the address
specified in the ADDR field.
When a write operation is selected, the value written to this field is
the value written to the serial EEPROM. When a read operation is
selected, the value written to this field is ignored and the value
read from the serial EEPROM may be read from this field when the
DONE bit is set.
24 BUSY RO 0x0 EEPROM Busy. This bit is set when a serial EEPROM read or
write operation is in progress.
0x0 -(idle) serial EEPROM interface idle
0x1 -(busy) serial EEPROM interface operation in progress
25 DONE RW1C 0x0 EEPROM Operation Completed. This bit is set when a serial
EEPROM operation has completed.
0x0 -(notdone) interface is idle or operation in progress
0x1 -(done) operation completed