Rastergraf Eclipse3 Series User Manual page 77

Rastergraf
3.8 Talk To Me Through I
The Borealis chip has a control register that is used to implement the I
protocol, a 2 wire serial bus designed Philips Semiconductor. The Borealis
is the I
in the Borealis chip. The I
"acknowledge" states, so it is possible to probe for these devices and
determine whether they exist.
2
I C is used to control the following devices:
Micrel MIC74 8-bit I/O register (optional)
THC63DV164 DVI digital video encoder/transmitter (optional)
LM75 thermal sensor (optional)
AT24C02 2 Kbit serial EEPROM
the Display Monitor
2
An I C device is determined by a combination of device internal bits (bits
4-7) and (usually) three pins that are wired by the board designer (bits 1-3)
Bit 0 is used to denote a Read (1) or Write (0) operation.
Because the Eclipse3 board serial EEPROM and the Display Monitor have
a common I
multiplexer on the Borealis board (see Section 3.5) that selects between
on-board I
The LM75 must be read in 2 byte increments, otherwise it will hang the
2
I C bus. Since most vendors combine the R/W bit with the actual I
address (e.g. write @ 0x88, read @ 0x89), the following table uses that
convention.
2
C master and it controls the bus through the DDC control register
2
C bus supports specific "start", "stop" and
2
C address (and this is not allowed) there is a 2 way
2
C devices and the Display Monitor.
2
Table 3-5 I C Device Addresses
Device R/W
W
MIC74
R
W
THC63DV164
R
W
LM75
R
W
AT24C02
R
W
Display Monitor
R
2
C
Binary Hex
0100 0000 0x40
0100 0001 0x41
0111 0000 0x70
0111 0001 0x71
1001 1100 0x9C
1001 1101 0x9D
1010 1000 0xA8
1010 1001 0xA9
1010 1000 0xA8
1010 1001 0xA9
Programming On-board Devices 3-19
2
C
2
C
I2CMUX
x
x
1
1
1
1
1
1
0
0