UPD77111 datasheet(23/80 Pages) NEC

23 / 80 page

Data Sheet U12801EJ4V0DS00

µµµµPD77110, 77111, 77112

2.4.4 Wait cycle register

The number of wait cycles to be inserted when the external data memory area is accessed can be specified in

advance by using a register (DWTR)

Note. The number of wait cycles that can be set is 1, 3, or 7.

Note This function is not available on the

µPD77111 because this DSP does not have an external data area.

3. CLOCK GENERATOR

The clock generator generates an internal system clock based on the external clock input from the CLKIN pin and

supplies the generated clock to the internal units of the DSP.

For details of how to set the PLL multiple, refer to 4.2 Initializing PLL, 8.1 Clock Control Options, and 8.3.1

Settings related to clock control.

Stop mode

PLL control circuit

Output divider

Halt divider

Halt mode

Internal

system clock

×m

CLKOUT

CLKIN

÷n

÷l

4. RESET FUNCTION

When a low level of a specified width is input to the RESET pin, the device is initialized.

4.1 Hardware Reset

If the RESET pin is asserted active (low level) for a specified period, the internal circuitry of the DSP is initialized.

If the RESET pin is then deasserted inactive (high level), boot processing of the instruction RAM is performed

according to the status of the port pins (P0 and P1). After boot processing, processing is executed starting from the

instruction at address 0x200 of instruction memory (reset entry).

On power application, the RESET pin must be asserted active (low level) after 4 input clocks have been input with

the RESET pin in the inactive status (high level), after the supply voltage has reached the level of the operating

voltage. In other words, no power-ON reset function is available. On power application, the PLL must be initialized.

UPD77111 Datasheet(PDF) 23 Page - NEC