Sharp MZ-3500 service manual Wl -», «--N

M Z 3500
DO~D7	Data Bas
RXD	Receive Data (IN/OUT)
WR	Write (IN)
RD	Read (IN)
C/D	Control/Data (IN/OUT)
CS	Chip Select (IN)
DSR	Data Set Ready (IN)
DTR	Data Terminal Ready (OUT)
RTS	Request to Send (OUT)
CTS	Clear to Send (IN)
TXRDY	. Transmitter Ready (OUT)
TXC	Transmitter Clock (IN)
TXE	. Transmitter Empty (OUT)
RXC	. Receiver Clock (IN)
SYNET/BD	: SYNC Detect/Break Detect (IN/OUT)

2)UPD8253C-5 (Programmable Interval Timer)

The UPD8253-5 is a programmable counter/timer speci- fically designed for the 8-bit microcomputer system. It consists of three sets of 16-bit counters that operate under a maximum counter rate of 4MHz. Timer and six operational modes are programmed to be used for a wide range of microcomputer system timing control.

Features

•Z-80 compatible

•Three sets of 16-bit counters

•DC-4MHz of count rate

•Programmable six operational modes and timer duration

•Choice of binary counter/BCD counter

•N-channel MOS, input/output TTLcompatible

•Single +5Vsupply, 24-pin DIP

•Intel 8253-5 compatible

Pin configuration (Top View)

.VCC

Block diagram

	O	Data bus						Counter	•«	t 1 KO
UO			AA			VV			<l	C . MtO
		buffer						# 0
			v-v						'	*-"no
					l		_t
		write			Interna			# 1	<	OA1 ^ 1
wl —»<:		Read/				/«--N		Counter	<	C 1 K 1
AO	1	logic				\r,V
Al	>				£					»-()l I 1
c-		^						t
		^
		Control	—					Counter	*-	Cl K2
			/"	'
		word				A^S			«	GA1L2
		register	**w			S1—K]		# 2
										KHT2
		1						t
		D7-DO		Data Bus (8 bit)
		CLKN		Counter Clock Inputs
		GATEN		Counter Gate Inputs
		OUTN		Counter Outputs
		RD		. Read Counter
		WR		Write Command or Data
		CS		Chip Select
		A1~AO		: Counter Select
		Vcc		. +5 Volts
		GND		. Ground

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