CP8056S データシートの表示（PDF） - Unspecified

部品番号

コンポーネント説明

メーカー

CP8056S

EPROM/ROM-Based 8-Bit Microcontroller Series

Unspecified 

CHENGPIN

CP8056

2.1.2 TMR0 (Time Clock/Counter register)

Address

Name

B7

B6

B5

B4

B3

B2

B1

B0

01h (r/w)

TMR0

8-bit real-time clock/counter

The Timer0 is a 8-bit timer/counter. The clock source of Timer0 can come from the instruction cycle clock or by an

external clock source (T0CKI pin) defined by T0CS bit (OPTION<5>). If T0CKI pin is selected, the Timer0 is

increased by T0CKI signal rising/falling edge (selected by T0SE bit (OPTION<4>)).

The prescaler is assigned to Timer0 by clearing the PSA bit (OPTION<3>). In this case, the prescaler will be cleared

when TMR0 register is written with a value.

2.1.3 PCL (Low Bytes of Program Counter) & Stack

Address

Name

B7

B6

B5

B4

B3

B2

B1

B0

02h (r/w)

PCL

Low order 8 bits of PC

CP8056 devices have 10-bit wide Program Counter (PC) and five-level deep 10-bit hardware push/pop stack. The

low byte of PC is called the PCL register. This register is readable and writable. The high byte of PC is called the

PCH register. This register contains the PC<9:8> bits and is not directly readable or writable. All updates to the PCH

register go through the PCHBUF register. As a program instruction is executed, the Program Counter will contain

the address of the next program instruction to be executed. The PC value is increased by one, every instruction

cycle, unless an instruction changes the PC.

For a GOTO instruction, the PC<9:0> is provided by the GOTO instruction word. The PCL register is mapped to

PC<7:0>, and the PCHBUF register is not updated.

For a CALL instruction, the PC<9:0> is provided by the CALL instruction word. The next PC will be loaded (PUSHed)

onto the top of STACK. The PCL register is mapped to PC<7:0>, and the PCHBUF register is not updated.

For a RETIA, RETFIE, or RETURN instruction, the PC are updated (POPed) from the top of STACK. The PCL

register is mapped to PC<7:0>, and the PCHBUF register is not updated.

For any instruction where the PCL is the destination, the PC<7:0> is provided by the instruction word. However, the

PC<9:8> will come from the PCHBUF<1:0> register (PCHBUF Æ PCH).

PCHBUF register is never updated with the contents of PCH.

P.7/CP8056

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