HD6413258F10V Datasheet, PDF (130/301 Pages) Renesas Technology Corp – Regarding the change of names mentioned in the document, such as Hitachi Electric and Hitachi XX, to Renesas Technology Corp.

Sending H8/325
Write
P3DR
Receiving H8/325
Interrupt
request
Read
HCSR
Interrupt
request
Read
P3DR
Read
HCSR
Write
P3DR
P3 7 to P3 0
P3 7 to P3 0
OS
IS
IS
OS
H8/325
(sending chip)
P3DR: Port 3 data register
HCSR: Handshake control/Status register
H8/325
(receiving chip)
Figure 6-7. Parallel Handshaking Interface Timing Chart (Example)
1. The sending and receiving H8/325s set their HCSR bits as follows:
Sending H8/325: ISIE = 1, OSE = 1, OSS = 1, LTE = 0, BSE = 0.
Receiving H8/325: ISIE = 1, OSE = 1, OSS = 0, LTE = 1, BSE = 0.
2. The sending H8/325 writes the transmit data in the port 3 data register (P3DR). This generates
an output strobe signal, notifying the receiving H8/325 of data output.
Fig 6-7
3. The receiving H8/325 receives the strobe on its input strobe line and latches the data in port 3.
ISF is set to 1, generating an input strobe interrupt.
4. The receiving H8/325 reads HCSR, then reads the received data from P3DR. This clears ISF to
0 and generates an output strobe signal, notifying the sending H8/325 that the data have been
received.
5. The input strobe line of the sending H8/325 goes low, setting ISF and generating an input strobe
interrupt.
6. The sending H8/325 reads HCSR, then writes the next transmit data in P3DR. (If it has no next
data to send, it should read P3DR.) This clears ISF to 0 and generates an output strobe signal.
The process now returns to step 3.
6.3.5 Interrupts
Regardless of the operating mode or the value of the LTE bit, ISF is always set to 1 when the IS
input changes from high to low. If ISIE is set to 1, an input strobe interrupt (ISI) is requested. In the
software standby mode, LTE must also be set. See section 6.3.3, Operation in Software Standby
Mode.
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