UPD78F0988AGC-8BS Renesas Electronics America, UPD78F0988AGC-8BS Datasheet - Page 282

• Manufacturer Part Number: UPD78F0988AGC-8BS
• Manufacturer: Renesas Electronics America

Specifications of UPD78F0988AGC-8BS

• Lead Free Status / Rohs Status: Supplier Unconfirmed

15.1 External Device Expansion Function
RAM, and SFR areas. To connect an external device, ports 4 and 6 are used. Port 4 controls address/data, read/
write strobe, wait, and address strobe signals.
an external access area in the SFR area, the PD780988 can be expanded with 16 bytes of external memory.
280
The external device expansion function is for connecting an external device to areas other than the internal ROM,
The PD780982, 780983, 780984, and 780986 can be expanded with 256 bytes of external memory. By using
Caution The external device expansion function can only be used under conditions of f
Caution When the external wait function is not used, the WAIT pin can be used as a port pin in all the
lower, and V
modes.
Table 15-2. Status of Ports 4 and 6 in External Memory Expansion Mode
External Expansion Mode
Single-chip mode
256-byte memory expansion mode
CHAPTER 15 EXTERNAL DEVICE EXPANSION FUNCTION
Table 15-1. Pin Functions in External Memory Expansion Mode
AD0 to AD7
DD
Pin Function when External Device is Connected
Name
ASTB
WAIT
= 4.0 to 5.5 V.
WR
RD
Multiplexed address/data bus
Read strobe signal
Write strobe signal
Wait signal
Address strobe signal
User’s Manual U13029EJ7V1UD
Port
Function
Port
Address/data
Port 4
0 to 7
Port
RD, WR, WAIT, ASTB
4
P40 to P47
Alternate
Function
5
Port 6
P64
P65
P66
P67
6
7
X
= 8.38 MHz or