mc68hc05p4a Freescale Semiconductor, Inc, mc68hc05p4a Datasheet - Page 43

• Manufacturer Part Number: mc68hc05p4a
• Description: M68hc05 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Chapter 10
Self-Check Mode
10.1 Introduction
The self-check program resides at mask ROM (read-only memory) locations $1F00 to $1FEF. This
program is designed to check the part’s functionality with a minimum of support hardware. The computer
operating properly (COP) subsystem is disabled in the self-check mode so that routines that feed the COP
do not exist in the self-check program.
10.2 Functional Description
The self-check mode is entered on the rising edge of RESET if the IRQ pin is driven to double the supply
voltage and the TCAP/PD7 pin is at logic 1. RESET must be held low for 4064 cycles after power-on reset
(POR) or for a time, t
(RAM), ROM, timer, simple serial input/output port (SIOP), and interrupts are tested. Self-check results
(using light-emitting diodes (LEDs) as monitors) are shown in
user code use any of the self-check code. The self-check code is subject to change at any time to improve
testability or manufacturability.
Figure 10-1
Freescale Semiconductor
illustrates a self-check circuit.
RL,
Note:
0 indicates LED is on; 1 indicates LED is off.
PC2
for any other reset. After reset, the input/output (I/O), random-access memory
0
0
0
1
1
1
All others
Table 10-1. Self-Check Results
Flashing
MC68HC05P4A Data Sheet, Rev. 7.1
PC1
0
1
1
0
0
1
PC0
1
0
1
0
1
0
Table
Bad I/O
Bad RAM
Bad timer
Bad ROM
Bad serial
Bad interrupt
Good device
Bad device
10-1. It is not recommended that the
Remarks
43