P87C51RB2BBD datasheet(55/67 Pages) PHILIPS

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Philips Semiconductors

Product data

P87C51RA2/RB2/RC2/RD2

80C51 8-bit microcontroller family 8KB/16KB/32KB/64KB OTP

with 512B/1KB RAM, low voltage (2.7 to 5.5 V), low power, high

speed (30/33 MHz)

2003 Jan 24

EPROM CHARACTERISTICS

All these devices can be programmed by using a modified Improved

Quick-Pulse Programming

™ algorithm. It differs from older methods

in the value used for VPP (programming supply voltage) and in the

width and number of the ALE/PROG pulses.

The family contains two signature bytes that can be read and used

by an EPROM programming system to identify the device. The

signature bytes identify the device as being manufactured by

Philips.

Table 8 shows the logic levels for reading the signature byte, and for

programming the program memory, the encryption table, and the

security bits. The circuit configuration and waveforms for quick-pulse

programming are shown in Figures 47 and 48. Figure 49 shows the

circuit configuration for normal program memory verification.

Quick-Pulse Programming

The setup for microcontroller quick-pulse programming is shown in

Figure 47. Note that the device is running with a 4 to 6MHz

oscillator. The reason the oscillator needs to be running is that the

device is executing internal address and program data transfers.

The address of the EPROM location to be programmed is applied to

ports 1 and 2, as shown in Figure 47. The code byte to be

programmed into that location is applied to port 0. RST, PSEN and

pins of ports 2 and 3 specified in Table 8 are held at the ‘Program

Code Data’ levels indicated in Table 8. The ALE/PROG is pulsed

low 5 times as shown in Figure 48.

To program the encryption table, repeat the 5 pulse programming

sequence for addresses 0 through 1FH, using the ‘Pgm Encryption

Table’ levels. Do not forget that after the encryption table is

programmed, verification cycles will produce only encrypted data.

To program the security bits, repeat the 5 pulse programming

sequence using the ‘Pgm Security Bit’ levels. After one security bit is

programmed, further programming of the code memory and

encryption table is disabled. However, the other security bits can still

be programmed.

Note that the EA/VPP pin must not be allowed to go above the

maximum specified VPP level for any amount of time. Even a narrow

glitch above that voltage can cause permanent damage to the

device. The VPP source should be well regulated and free of glitches

and overshoot.

Program Verification

If security bits 2 and 3 have not been programmed, the on-chip

program memory can be read out for program verification. The

address of the program memory locations to be read is applied to

ports 1 and 2 as shown in Figure 49. The other pins are held at the

‘Verify Code Data’ levels indicated in Table 8. The contents of the

address location will be emitted on port 0. External pull-ups are

required on port 0 for this operation.

If the 64 byte encryption table has been programmed, the data

presented at port 0 will be the exclusive NOR of the program byte

with one of the encryption bytes. The user will have to know the

encryption table contents in order to correctly decode the verification

data. The encryption table itself cannot be read out.

Reading the Signature Bytes

The signature bytes are read by the same procedure as a normal

verification of locations 030H and 031H, except that P3.6 and P3.7

need to be pulled to a logic low. The values are:

(030H) = 15H indicates manufactured by Philips

(031H) = CAH indicates 87C51RA2

CBH indicates 87C51RB2

CCH indicates 87C51RC2

CDH indicates 87C51RD2

(060H) = NA

Program/Verify Algorithms

Any algorithm in agreement with the conditions listed in Table 8, and

which satisfies the timing specifications, is suitable.

Security Bits

With none of the security bits programmed the code in the program

memory can be verified. If the encryption table is programmed, the

code will be encrypted when verified. When only security bit 1 (see

Table 9) is programmed, MOVC instructions executed from external

program memory are disabled from fetching code bytes from the

internal memory, EA is latched on Reset and all further programming

of the EPROM is disabled. When security bits 1 and 2 are

programmed, in addition to the above, verify mode is disabled.

When all three security bits are programmed, all of the conditions

above apply and all external program memory execution is disabled.

Encryption Array

64 bytes of encryption array are initially unprogrammed (all 1s).

™Trademark phrase of Intel Corporation.

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