M16C6K9 Datasheet, PDF (222/292 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

M16C/6K9 Group
PS2 Interface
q Transmission operation
Fig.GK-10 shows the transmission operation timing.
1
2
3
3
3
3
3
3
3
3
3
3
4
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DAT
(Device side DAT)
(Controller side DAT)
CLK
(Device side CLK)
(Controller side CLK)
Transmission enable flag
Transfer completion flag
Interrupt request
start
D0 D1 D2 D3 D4 D5 D6 D7 parity stop ack
start
D0 D1 D2 D3 D4 D5 D6 D7 parity stop
Fig.GK-10 Transmission operation timing
(1) Data writing
Write transmission data to PS2i shift register (address : 02A016, 02A416, 02A816). At this time,PS2 data
will become “L” (transmission start).
(2) Transmission enable
Set 0216 (Transmission enable bit = “1”) to PS2i control register (address : 02A216, 02A616, 02AA16) for
enabling transmission operation. At this time , PS2 clock (CLK) will become “H”.
(3) Data transmission (The transmission of data, parity and stop bits)
The content of PS2i shift register (address : 02A016, 02A416, 02A816) will be output to the PS2 data
(DAT) sequentially by the falling edge of PS2 clock (CLK). The sequence of data transfer is data bits (D0
to D7) , Parity bit, and stop bit.
(4) Acknowledge reception
The content of acknowledge bit will be read by the falling edge of PS2 clock (CLK).
(5) Communication completion
The communication opeartion is completed by detecting “H” on both PS2 clock (CLK) and PS2 data
(DAT). After the update of error flag (bit 4 - 6 of PS2i status register), the transfer completion flag (bit 0 of
PS2i status register) is set to “1” and the reception enable bit (bit 0 of PS2i control register) is cleared to
“0”. At this time, PS2 clock (CLK) becomes “L” (reception disable status) and the interrupt request occurs.
(6) Status clear
Read out the data from PS2i shift register (address : 02A016, 02A416, 02A816). At this time , the error flags
(bits 4 to 6) and transfer completion flag (Bit0) of PS2i status register (address : 02A116, 02A516, 02A916)
will be cleared to “0”.
Rev.1.00 Jun 06, 2003 page 222 of 290