
DDC MODULE
S3C8639/C863A/P863A/C8647/F8647
17-2
DDC CONTROL REGISTER (DCON)
The programmable DCON register to control the DDC is located at E9H in set 1, bank 1. It is read/write
addressable. Only four bits are mapped in this register.
The DCON.0 setting lets you detect falling edges at the serial clock, SCL0. If the DCON.0 is set to "0", the SCL0
(serial clock) is still high after reset (when read), or the bit can be cleared by S/W written "0" (when write). If the
DCON.1 is set to "1", falling edge is detected at SCL0 pin after RESET or after this bit is cleared by S/W.
NOTE
When the DDC interrupt is occurred, SCL0 line is not pull-down at the following cases:
— DDC1 mode
— Tx/Rx pre-buffer data registers ‘enable’ bit, DCON.3 is "1" (only slave mode).
The DCON.1 setting lets you select normal IIC-bus interface mode or DDC1 transmit mode. If you select normal
IIC-bus interface mode (DCON.1 = "0"), SCL0 pin is selected for clock line and the SCL0 falling edge (SCLF)
interrupt is disabled. Or if you select DDC1 transmit mode (DCON.1 = "1"), VCLK pin is selected for clock line
and the SCLF interrupt is enable.
The DCON.2 is a DDC address match bit and read-only. When the received DDC address matches to DAR0
register, DCON.2 is "1". And when it is start, stop or reset condition, DCON.2 is "0". To enable transmit or receive
pre-buffer data register, DCON.3 is used. When the transmit or receive pre-buffer data register is not used,
DCON.3 is "0" (normal IIC-bus mode). DCON.3 is set by writing One to it or by reset. If DCON.3 is "1", the
transmit or receive pre-buffer data register is enable.
DDC Control Register (DCON)
E9H, Set 1, Bank 1, R/W (Bit 2 is read-only)
-
.3
.2
.1
.0
MSB
LSB
SCL0 (Serial Clock) falling
edge detection bit (SCLF):
0 = SCL0 is high after
RESET (when read)
0 = Cleared by S/W written
"0" (when write)
1 = Falling edge is detected
(when read)
1 = No effect (when write)
Not used for the
S3C8639/C863A/C8647
DDC1 transmit mode enable bit:
0 = IIC-bus interface mode
(SCL0 pins is also selected)
1 = DDC1 transmit mode
(VCLK pin is also selected)
Transmit or receive pre-buffer data register
enable bit:
0 = Normal IIC-bus mode
(Pre-buffer data registers are not used)
1 = Pre-buffer data registers enable mode
(This bit is set by writing one to it or by
reset)
DDC address match bit (read-only):
0 = When start or stop or reset
1 = When the received DDC address
matches to DAR0 register
Figure 17-1. DDC Control Register (DCON)