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3-4
MSM66591/ML66592 User's Manual
Chapter 3 CPU Architecture
[1]
Accessing Program Memory Space
Program memory space is usually accessed by the program counter (PC) and the code
segment register (CSR). However, when a ROM table reference instruction
(LC A, obj...etc.) or a ROM window function (see Section 5.1) is executed, program
memory space is accessed by the content of the table segment register (TSR) and the
register specified by the instruction.
Accessing the internal ROM area and the external memory (ROM) area of the program
memory space is automatically switched by an internal MSM66591/ML66592 operation
by the status of the
EA
pin (input: pin 3).
When "H" level is input to the
EA
pin, the internal program memory area is accessed for
the entire program address. When "L" level is input to the
EA
pin, the external program
memory area is accessed for the entire program address.
If the external memory area of the program memory space is accessed with the
EA
pin
in "L" level, Port 0 (I/O: pins 72–79: output of low address and input of data), Port 1
(output: pins 82–89: output of high address) and P12_0/A16 pin (output: pin 90: output
of code segment) operates as the bus port, and the P7_3/
PSEN
pin (output: pin 56)
becomes active synchronizing with the P7_2/ALE pin (output: pin 55). In ML66592,
P12_1/A17 (output: pin 91: output of code segment) also operates as a bus port.
In MSM66591, the internal program fetch enable area is 00000H–1FFFDH. This means
that the final address of instruction code must not exceed 1FFFDH. The final address of
the table data is 1FFFFH.
In ML66592, the internal program fetch enable area is 00000H–2FFFDH. This means
that the final address of instruction code must not exceed 2FFFDH. The final address of
the table data is 2FFFFH.
Segment 3 is not provided in the ML66592. Therefore, do not access address 30000H
or later.
[2]
Vector Table Area
The 74-byte area and 12-byte area of program memory space, which are 0000H–0049H
and 006AH–0074H in segment 0 respectively, are the vector table area (43 types). This
program memory space is used to store branch addresses caused by reset by
RES
(input:
pin 2) input, reset by execution of BRK instruction, reset by watchdog timer (WDT) overflow,
and reset by an operation code trap (OPTRP). It is also used to store branch addresses by
various interrupt requests.
If a reset or interrupt occurs, a 2-byte content of a branch address, stored in the corre-
sponding vector table, is loaded to the PC (an even address is insignificant data, the
following odd address is significant data), while at the same time "0" is loaded to the
CSR, and program execution starts from the loaded address in segment 0. Therefore, if
the reset or interrupt occurs during execution of the instruction for segment 1, the
program is executed from an address in segment 0.
If this area is not used as a vector table area, it can be used as a normal program area.
Summary of Contents for ML66592
Page 15: ...Contents 12 ...
Page 17: ......
Page 18: ...Overview Chapter 1 1 ...
Page 19: ......
Page 30: ...Description of Pins Chapter 2 2 ...
Page 31: ......
Page 44: ...CPU Architecture Chapter 3 3 ...
Page 45: ......
Page 101: ...3 56 MSM66591 ML66592User sManual Chapter 3 CPU Architecture ...
Page 102: ...CPU Control Functions Chapter 4 4 ...
Page 103: ......
Page 111: ...4 8 MSM66591 ML66592User sManual Chapter 4 CPU Control Functions ...
Page 112: ...Memory Control Functions Chapter 5 5 ...
Page 113: ......
Page 117: ...5 4 MSM66591 ML66592User sManual Chapter 5 Memory Control Functions ...
Page 118: ...Port Functions Chapter 6 6 ...
Page 119: ......
Page 152: ...Output Pin Control Pin OE Chapter 7 7 ...
Page 153: ......
Page 155: ...7 2 MSM66591 ML66592User sManual Chapter 7 Output Pin Control Pin OE ...
Page 156: ...Clock Generation Circuit Chapter 8 8 ...
Page 157: ......
Page 160: ...Time Base Counter TBC Chapter 9 9 ...
Page 161: ......
Page 164: ...Watchdog Timer WDT Chapter 10 10 ...
Page 165: ......
Page 170: ...Flexible Timer FTM Chapter 11 11 11 ...
Page 171: ......
Page 213: ...11 42 MSM66591 ML66592User sManual Chapter 11 Flexible Timer FTM ...
Page 214: ...General Purpose 8 Bit Timer Function Chapter 12 12 ...
Page 215: ......
Page 223: ...12 8 MSM66591 ML66592User sManual Chapter 12 General Purpose 8 Bit Timer Function ...
Page 224: ...PWM Functions Chapter 13 13 ...
Page 225: ......
Page 244: ...Baud Rate Generator Functions Chapter 14 14 ...
Page 245: ......
Page 263: ...14 18 MSM66591 ML66592User sManual Chapter 14 Baud Rate Generator Functions ...
Page 264: ...Serial Port Functions Chapter 15 15 ...
Page 265: ......
Page 348: ...A D Converter Functions Chapter 16 16 ...
Page 349: ......
Page 381: ...16 32 MSM66591 ML66592User sManual Chapter 16 A D Converter Functions ...
Page 382: ...Transition Detector Functions Chapter 17 17 ...
Page 383: ......
Page 387: ...17 4 MSM66591 ML66592User sManual Chapter 17 Transition Detector Functions ...
Page 388: ...Peripheral Functions Chapter 18 18 ...
Page 389: ......
Page 392: ...External Interrupt Request Function Chapter 19 19 ...
Page 393: ......
Page 396: ...Interrupt Request Processing Function Chapter 20 20 ...
Page 397: ......
Page 407: ...20 10 MSM66591 ML66592User sManual Chapter 20 Interrupt Request Processing Function ...
Page 408: ...Bus Port Functions Chapter 21 21 ...
Page 409: ......
Page 413: ...21 4 MSM66591 ML66592User sManual Chapter 21 Bus Port Functions ...
Page 414: ...Expansion Port Chapter 22 22 ...
Page 415: ......
Page 420: ...Serial Port with FIFO SCI5 Chapter 23 23 ...
Page 421: ......
Page 431: ...23 10 MSM66591 ML66592User sManual Chapter 23 Serial Port with FIFO SCI5 ...
Page 432: ...RAM Monitor Function Chapter 24 24 ...
Page 433: ......
Page 441: ...24 8 MSM66591 ML66592User sManual Chapter 24 RAM Monitor Function ...
Page 442: ...25 Electrical Characteristics Chapter 25 ...
Page 443: ......
Page 458: ...Package Dimensions Chapter 26 26 ...
Page 459: ......
Page 461: ...26 2 MSM66591 ML66592User sManual Chapter 26 Package Dimensions ...
Page 462: ...Revision History Chapter 27 27 ...
Page 463: ......
Page 465: ...27 2 MSM66591 ML66592User sManual Chapter 27 Revision History ...