UPD77112 データシートの表示（PDF） - NEC => Renesas Technology

部品番号

コンポーネント説明

メーカー

UPD77112

16-BIT FIXED-POINT DIGITAL SIGNAL PROCESSORS

NEC => Renesas Technology 

µPD77110, 77111, 77112

5.1.1 Self boot

The boot-up ROM transfers the instruction code stored in the data memory space to the instruction RAM, based

on the boot parameter written to address 0x4000 of the Y data memory. Generally, with a mask ROM model

(µPD77111 or 77112), this function is implemented by storing the instructions to be booted in the data ROM.

In addition, the instructions to be booted can be also stored in an external data area in the form of flash ROM, and

self boot can be executed from this external data area.

With the µPD77110, the value of address 0x4000 of the Y data memory is undefined on power application,

because this address is in RAM. Therefore, with the µPD77110, the self boot mode cannot be selected on power

application, and host boot must be executed. This also applies when the PLL is initialized. By writing a boot

parameter to address 0x4000 or those that follow of the Y data memory, self boot can be executed when the RESET

signal is subsequently input (except the reset that initializes the PLL). In this case, however, the instructions to be

booted are only those at address 0x0200 through 0x0FFF of the instruction RAM.

5.1.2 Host boot

In this boot mode, a boot parameter and instruction code are obtained via the host interface, and transferred to the

instruction RAM.

With the µPD77110, the host boot mode is used on power application. The boot instruction area is the instruction

RAM from addresses 0x0200 through 0x0FFF. To boot up the instruction RAM from 0x4000 through 0xBFFF, host

reboot is used.

5.2 Reboot

By calling the next reboot entry from the program, the contents of the instruction RAM can be rewritten. In

particular, the µPD77110 has a reboot function that boots up the instruction RAM from 0x4000 through 0xBFFF.

Self boot

Host boot

Reboot Mode

X memory

Y memory

Host reboot

Word reboot

Byte reboot

Word reboot

Byte reboot

Entry Address

0x2

0x4

0x1

0x3

0x6 (µPD77110)

0x5 (µPD77111, 77112)

5.2.1 Self reboot

The instruction codes stored in the data memory are transferred to the instruction RAM.

This boot mode cannot be used with the µPD77110.

Set the following parameters and call the entry address of the corresponding reboot mode to execute self reboot.

• R7L : Number of instruction steps for rebooting

• DP3: First address of X memory in which instruction codes are stored (in the case of reboot from X memory),

or first address of the instruction memory to be loaded (in the case of reboot from Y memory)

• DP7: First address of instruction memory to be loaded (in the case of reboot from X memory), or first address

of X memory in which instruction codes are stored (in the case of reboot from Y memory)

Data Sheet U12801EJ4V0DS00

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