UPD78P4908 datasheet(21/64 Pages) NEC

21 / 64 page

µPD78P4908

Data Sheet U11681EJ2V0DS00

(1) Read mode

Set CE to L and OE to L to set read mode.

(2) Output disable mode

Set OE to H to set high impedance for data output and output disable mode.

Consequently, if several

µPD78P4908 devices are connected to a data bus, the OE pins can be controlled to

select data output from any of the devices.

(3) Standby mode

Set CE to H to set standby mode.

In this mode, data output is set to high impedance regardless of the OE setting.

(4) Page data latch mode

At the beginning of page write mode, set CE to H, PGM to H, and OE to L to set page data latch mode.

In this mode, 1 page (4 bytes) of data are latched to the internal address/data latch circuit.

(5) Page write mode

After latching the address and data for one page (4 bytes) using page data latch mode, adding a 0.1 ms program

pulse (active, low) to the PGM pin with both CE and OE set to H causes page write to be executed. Later, setting

both CE and OE to L causes program verification to be executed.

If programming is not completed after one program pulse, the write and verify operations may be repeated X times

(where X

≤ 10).

(6) Byte write mode

Adding a 0.1 ms program pulse (active, low) to the PGM pin with setting CE to L and OE to H causes byte write

to be executed. Later, setting OE to L causes program verification to be executed.

If programming is not completed after one program pulse, the write and verify operations may be repeated X times

(where X

≤ 10).

(7) Program verify mode

Set CE to L, PGM to H, and OE to L to set program verify mode. Use verify mode for verification following each

write operation.

(8) Program inhibit mode

Program inhibit mode is used to write to a single device when several

µPD78P4908 devices are connected in

parallel to OE , VPP, and D0 to D7 pins.

Use the page write mode or byte write mode described above for each write operation. Write operations cannot

be done for devices in which the PGM pin has been set to H.

UPD78P4908 Datasheet(PDF) 21 Page - NEC