Intel mcs-48 manual PROGRAMMING, VERIFYING, and Erasing the 8741A Eprom, Voo

8041 AJ8641AJ8741 A

CRYSTAL OSCILLATOR MODE

r----- XTALI

I

I

<16 pF ,~..I

(INCLUDES XTAL,

SOC~ET, STRAY) I

I

LI ____ _

3 XTAL2

16-26 pF I

(INCLUDES SOCKET, STRAY) ':"

CRYSTAL SERIES RESISTANCE SHOULD BE <75Q AT 6 MHz; <180Q AT 3.6 MHz.

DRIVING FROM EXTERNAL SOURCE

+5V

4702

Jo--+------ =-lXTALI

+5V

470Q

'---~---=-j XTAL2

BOTH XTALI AND XTAL2 SHOULD BE DRIVEN. RESISTORS TO Vee ARE NEEDED TO ENSURE V,H = 3.8V

IF TTL CIRCUITRY IS USED.

LC OSCILLATOR MODE

J,.	..Q.	NOMINAL I
45.H	20 pF	5.2 MHz
120.H	20 pF	3.2 MHz

.....---.----"-1 XTAL 1

CPP" 5-10 pF PIN·TO·PIN

' --......-~XTAL2CAPACITANCE

EACH C SHOULD BE APPROXIMATELY 20 pF.INCLUDING STRAY CAPACITANCE.

PROGRAMMING, VERIFYING, AND ERASING THE 8741A EPROM

Programming Verification

In brief, the programming process consists of: activating the program mode, applying an address, latching the address, applying data, and applying a programming pulse. Each word is programmed completely before moving on to the next and is followed by a verification step. The follow- ing is a list of the pins used for programming and a descrip- tion of their functions:

Pin	Function
XTAL 1	Clock Input (1 to 6MHz)
Reset	Initialization and Address Latching
Test 0	Selection of Program or Verify Mode
EA	Activation of Program/Verify Modes
BUS	Addre~s and Data Input
	Data Output During Verify
P20-1	Address Input
VOO	Programming Power Supply
PROG	Program Pulse Input

WARNING:

An attempt to program a missocketed 8741 A will result in severe damage to the part. An indication of a properly socketed part is the

appearance of the SYNC clock output. The lack of this clock may be used to disable the programmer.

The Program/Verify seqUef1ce fs:

1.Aa = av, CS = SV, EA = SV, RESET =av, TESTa = SV, Voo = 5V, clock applied or internal oscillator operating, BUS and PROG floating.

2.Insert 8741A in programming socket

3.TEST a = Ov (select program mode)

4.EA = 23V (activate program mode)

S. Address applied to BUS and P2Q..1

6.RESET = Sv (latch address)

7.Data applied to BUS

8.V DO =2Sv (programm ing power)

9.PROG = Ov followed by one sOms pulse to 23V

10_ VOO = 5v

11.TEST 0 = Sv (verify mode)

12.Read and verify data on BUS

13.TEST 0 = Ov

14.RESET = Ov and repeat from step S

16.Programmer should be at conditions of step 1 when 8741A is removed from socket.

9·130 00188A