
CHAPTER 5 BUS CONTROL FUNCTION
User’s Manual U15905EJ2V1UD
178
Table 5-2. External Control Pins (Separate Bus)
Bus Control Pin
Alternate-Function Pin
I/O
Function
AD0 to AD15
PDL0 to PDL15
I/O
Data bus
A0 to A15
P90 to P915
Output
Address bus
A16 to A23
Note
PDH0 to PDH7
Output
Address bus
WAIT
PCM0
Input
External wait control
CLKOUT
PCM1
Output
Internal system clock
CS0 to CS3
PCS0 to PCS3
Output
Chip select
WR0, WR1
PCT0, PCT1
Output
Write strobe signal
RD
PCT4
Output
Read strobe signal
HLDRQ
PCM3
Input
HLDAK
PCM2
Output
Bus hold control
Note
A16 to A21 in the V850ES/SA2
5.2.1
Pin status when internal ROM, internal RAM, or internal peripheral I/O is accessed
When the internal ROM, internal RAM, or internal peripheral I/O is accessed, the status of each pin is as follows.
Table 5-3. Pin Status When Internal ROM, Internal RAM, or Internal Peripheral I/O Is Accessed
Separate Mode
Multiplexed Bus Mode
Address bus
(A23 to A0)
Undefined
Address bus
(A23 to A16)
Undefined
Data bus
(AD15 to AD0)
Hi-Z
Data bus
(AD15 to AD0)
Undefined
Control signal
Inactive
Control signal
Inactive
Caution
When the internal ROM area is write-accessed, the addresses, data, and control signals
are activated in the same way as access to the external memory area.
5.2.2
Pin status in each operation mode
For the pin status of the V850ES/SA2 and V850ES/SA3 in each operation mode, refer to 2.2 Pin Status.