Epson S1C6200 - Manual (Page 90)

84 EPSON S1C6200/6200A CORE CPU MANUAL
APPENDIX A. S1C6200A (ADVANCED S1C6200) CORE CPU
APPENDIX
A. S1C6200A (A
DVANCED
S1C6200) C
ORE
CPU
S1C6200A is an improved version of the S1C6200. In this section, S1C6200A is described only in
terms of its differences with S1C6200. It is recommended that users of S1C6200A read this section.
S1C6200A is a Core CPU which has been made easier to integrate software by improving the parts of the
S1C6200 CPU which are difficult to use.
This section lists its differences with S1C6200; for items which are not included here, refer to the corre-
sponding section in this manual.
A1 Outline of Differences
• The D (decimal) flag is set to "0" during initial reset.
• Modifications of the interrupt circuit
- The interrupt timing has been shifted to 0.5 clock later.
- In the 1-chip micro controller which uses S1C6200A, writing on the interrupt mask register
and reading the interrupt factor flag during EI (enable interrupt flag) are possible. (However, consult
the respective hardware manuals to find out whether these are possible with the CPU peripheral
circuits.)
A2 Detailed Description of the Differences
A2.1 Initial reset
The D (decimal) flag will be set as follows through initial reset:
Table A2.1.1 D (decimal) flag initial setting
D (decimal) flag setting
S1C6200
Undefined
S1C6200A
0
CPU Core
Owing to this, bugs due to omission of D (decimal) flag setting during software development can now be
easily prevented.
For the values of other registers and flags during initial reset, see Section 2.5.4, "Initial reset".
A2.2 Interrupt
Operation during interrupt issuance
The time it takes to complete interrupt processing by hardware after the Core CPU receives the interrupt
request has changed as follows:
Table A2.2.1 Required interrupt processing time
a) During instruction execution
b) At HALT mode
c) During PSET instruction execution
S1C6200
(clock cycles)
13 to 25
13 to 20
13 to 18
14 to 15
13 to 25
13 to 23
S1C6200A
(clock cycles)
12.5 to 24.5
12.5 to 19.5
12.5 to 17.5
14 to 15
12.5 to 24.5
12.5 to 22.5
Item
12-cycle instruction execution
7-cycle instruction execution
5-cycle instruction execution
PSET + CALL
PSET + JP
Figure A2.2.1 shows the timing chart of the S1C6200A interrupt.