h8s-2169 Renesas Electronics Corporation., h8s-2169 Datasheet - Page 596

• Manufacturer Part Number: h8s-2169
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 17 Keyboard Buffer Controller
Rev. 3.00 Jan 18, 2006 page 568 of 1044
REJ09B0280-0300
Receive data processing
(receive enabled state)
Receive enabled state
and KDI bits both
Clear KBF flag
Set KBIOE bit
Read KBCRH
Read KBBR
Set KBE bit
KBF = 1?
PER = 0?
KBS = 1?
KCLKI
Start
1?
Yes
Yes
Yes
Yes
Figure 17.3 Sample Receive Processing Flowchart
[1]
[2]
No
[3]
No
No
No
[6]
Keyboard side in data
Execute receive abort
Error handling
transmission state.
[4]
processing.
[5]
[1] Set the KBIOE bit to 1 in
[2] Read KBCRH, and if the
[3] Detect the start bit output
[4] When a stop bit is received,
[5] Perform receive data
[6] Clear the KBF flag to 0 in
The receive operation can be
continued by repeating steps
[3] to [6].
KBCRL.
KCLKI and KDI bits are
both 1, set the KBE bit
(receive enabled state).
on the keyboard side and
receive data in
synchronization with the fall
of KCLK.
the keyboard buffer
controller drives KCLK low
to disable keyboard
transmission (automatic I/O
inhibit).
If the KBIE bit is set to 1 in
KBCRH, an interrupt
request is sent to the CPU
at the same time.
processing.
KBCRL. At the same time,
the system automatically
drives KCLK high, setting
the receive enabled state.