DS80C320 datasheet(13/42 Pages) DALLAS

13 / 42 page

DS80C320/DS80C323

13 of 42

64-BYTE BLOCK MOVE WITH DUAL DATA POINTER

; SH and SL are high and low byte source address.

; DH and DL are high and low byte of destination address.

; DPS is the data pointer select. Reset condition is DPS=0, DPTR0 is selected.

# CYCLES

EQU

DPS, #86h

; TELL ASSEMBLER ABOUT DPS

MOV

R5, #64

; NUMBER OF BYTES TO MOVE

MOV

DPTR, #DHDL

; LOAD DESTINATION ADDRESS

INC

DPS

; CHANGE ACTIVE DPTR

MOV

DPTR, #SHSL

; LOAD SOURCE ADDRESS

MOVE:

; THIS LOOP IS PERFORMED THE NUMBER OF TIMES LOADED INTO R5, IN THIS EXAMPLE 64

MOVX

A, @DPTR

; READ SOURCE DATA BYTE

INC

DPS

; CHANGE DPTR TO DESTINATION

MOVX

@DPTR, A

; WRITE DATA TO DESTINATION

INC

DPTR

; NEXT DESTINATION ADDRESS

INC

DPS

; CHANGE DATA POINTER TO SOURCE

INC

DPTR

; NEXT SOURCE ADDRESS

DJNZ

R5, MOVE

; FINISHED WITH TABLE?

PERIPHERAL OVERVIEW

Peripherals in the DS80C320/DS80C323 are accessed using Special Function Registers (SFRs). The

device provides several of the most commonly needed peripheral functions in microcomputer-based

systems. These functions are new to the 80C32 family and include a second serial port, Power- fail Reset,

Power- fail Interrupt, and a programmable Watchdog Timer. These are described below, and more details

are available in the High-Speed Microcontroller User’s Guide.

SERIAL PORTS

The DS80C320/DS80C323 provides a serial port (UART) that is identical to the 80C32. Many

applications require serial communication with multiple devices. Therefore a second hardware serial port

is provided that is a full duplicate of the standard one. It optionally uses pins P1.2 (RXD1) and P1.3

(TXD1). This port has duplicate control functions included in new SFR locations. The second serial port

operates in a comparable manner with the first. Both can operate simultaneously but can be at different

baud rates.

The second serial port has similar control registers (SCON1 at C0h, SBUF1 at C1h) to the original. One

difference is that for timer-based baud rates, the original serial port can use Timer 1 or Timer 2 to

generate baud rates. This is selected via SFR bits. The new serial port can only use Timer 1.

TIMER RATE CONTROL

One important difference exists between the DS80C320/DS80C323 and 80C32 regarding timers. The

original 80C32 used a 12 clock per cycle scheme for timers and consequently for some serial baud rates

(depending on the mode). The DS80C320/DS80C323 architecture normally runs using 4 clocks per cyc le.

However, in the area of timers, it will default to a 12-clock per cycle scheme on a reset. This allows

existing code with real-time dependencies such as baud rates to operate properly. If an application needs

higher speed timers or serial baud rates, the timers can be set to run at the 4-clock rate.

The Clock Control register (CKCON - 8Eh) determines these timer speeds. When the relevant CKCON

bit is a logic 1, the device uses 4 clocks per cycle to generate timer speeds. When the control bit is set to a

0, the device uses 12 clocks for timer speeds. The reset condition is a 0. CKCON.5 selects the speed of

DS80C320 Arkusz danych(PDF) 13 Page - Dallas Semiconductor

DS80C320 Arkusz danych(HTML) 13 Page - Dallas Semiconductor

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

Arkusz danych Pobierz

Link URL