UPD77112GC Просмотр технического описания (PDF) - NEC => Renesas Technology

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UPD77112GC

16-BIT FIXED-POINT DIGITAL SIGNAL PROCESSORS

NEC => Renesas Technology 

µPD77110, 77111, 77112

When the PLL multiple is m, output division ratio is n, and halt division ratio is l, the relationship between each

operation mode and operating clock is as follows:

Operation Mode

Normal operation mode

HALT mode

STOP mode

Clock Supplied Inside DSP

m/n times external input clock

m/n/l times external input clock

Stopped

The PLL control circuit multiplies the input clock by an integer from 1 to 16. Specify the mask option of the PLL

multiple so that the multiplied frequency falls within the specified PLL lock frequency range.

The output divider divides the clock multiplied by the PLL by an integer from 1 to 16. Specify the mask option of

the output division ratio so that the frequency m/n times the external input clock supplied to the DSP falls within the

specified operating frequency range of the DSP.

The HALT divider functions only in the HALT mode. It divides the clock of the output divider by an integer from 1

to 16 and supplies the divided clock to the internal circuitry. Specify the mask option of the HALT division ratio so

that necessary division can be performed.

Whether the clock supplied to the internal circuitry of the DSP (internal system clock) is “output” or “not output”

from the CLKOUT pin can be specified. Specify the mask option as necessary.

If an odd value (other than 1) is specified as the output division ratio, the high-level width of the clock output from

the CLKOUT pin is equal to one cycle during normal operation (i.e., the clock does not have a duty factor of 50%).

8.2 WAKEUP Function

The WAKEUP pin can be used to release the STOP mode as well as a hardware reset.

If the STOP mode is released by means of a hardware reset, the status before the STOP mode was set cannot be

restored after the STOP mode has been released. If the WAKEUP pin is used, however, the status before the STOP

mode is set can be retained and program execution can be resumed starting from the instruction after the STOP

instruction.

Whether the WAKEUP pin is used to release the STOP mode can be specified by a mask option.

When the WAKEUP function is specified valid, the WAKEUP pin is multiplexed with the INT4 pin and it usually

functions as an interrupt pin. The pin functions as the WAKEUP pin only in the STOP mode (if this pin is asserted

active in the STOP mode, it is used only to release the STOP mode, and execution does not branch to an interrupt

vector).

8.3 Mask Option Equivalent Function of µPD77110

Because the µPD77110 does not have mask options, the multiple of the PLL cannot be specified in the same

manner as the µPD77111 and 77112. However, an external pin on the µPD77110 has a function equivalent to the

mask option. Care must be exercised when using the µPD77110, including when it is used to emulate the µPD77111

and 77112.

Data Sheet U12801EJ4V0DS00

31

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