M37735EHB 查看數據表（PDF） - MITSUBISHI ELECTRIC

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M37735EHB

MICROCOMPUTERS PROM VERSION OF M37735MHBXXXFP

MITSUBISHI ELECTRIC  

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MITSUBISHI MICROCOMPUTERS

M37735EHBXXXFP

M37735EHBFS

PROM VERSION OF M37735MHBXXXFP

BASIC FUNCTION BLOCKS

The M37735EHBXXXFP has the same functions as the

M37735MHBXXXFP except for the following:

(1) The built-in ROM is PROM.

(2) The status of bit 3 of the oscillation circuit control register 1 (address

6F16) at a reset is different.

(3) The usage condition of bit 3 of the oscillation circuit control register

1 is different.

(4) Part of the processor mode selection method is different.

Accordingly, refer to the basic function blocks description in the

M37735MHBXXXFP except for Figure 1 (bit configuration of

oscillation circuit control register 1), Figure 3 (microcomputer internal

status during reset), and Table 1 (microprocessor mode selection

method).

In the M37735EHBXXXFP, bit 3 of the oscillation circuit control register

1 must be “0”. (Refer to Figure 1.) Bit 3 is “1” at a reset. Accordingly,

write “0” to bit 3 in the single-chip mode after reset.

Figure 2 shows how to write data in oscillation circuit control register

1.

In the M37735EHBXXXFP, the microprosessor mode cannot be

selected by connecting the CNVSS pin to VCC. Connect the CNVSS

pin to VSS and start the microcomputer’s operating from the single-

chip mode.

Table 1. Relationship between CNVSS pin input level and processor

modes

CNVSS

Mode

Description

VSS · Single-chip

· Memory expansion

· Microprocessor

Single-chip mode upon starting

after reset. Each mode can be

selected by changing the

processor mode bits by software.

76543210

Address

0 0 CC2 CC1 CC0 Oscillation circuit control register 1 6F16

Main clock division selection bit

0 : Main clock is divided by 2.

1 : Main clock is not divided by 2.

Note. Write to the oscillation circuit control

register 1 as the flow shown in Figure 2.

Main clock external input selection bit

0 : Main-clock oscillation circuit is operating by itself.

Watchdog timer is used at returning from STP state.

1 : Main-clock is input externally.

Watchdog timer is not used at returning from STP state.

Sub clock external input selection bit

0 : Sub-clock oscillation circuit is operating by itself.

Port P76 functions as XCOUT pin.

Watchdog timer is used at returning from STP state.

1 : Sub-clock is input externally.

Port P76 functions as I/O port.

Watchdog timer is not used at returning from STP state.

0 : Always “0” (This bit is “1” at reset, so that write this bit to “0”.)

0 : Always “0” (However, writing data “5516” shown in Figure 2 is possible.)

Clock prescaler reset bit

Fig. 1 Bit configuration of oscillation circuit control register 1 (corresponding to Figure 63 in data sheet “M37735MHBXXXFP”)

Writing data “8016” (LDM instruction)

Reset clock prescaler

Writing data “5516” (LDM instruction)

Writing data “0Y16” (LDM instruction)

CC2 to CC0 selection bits

Next instruction

• How to reset clock prescaler

• How to write in CC2 to CC0 selection bits

Note. “Y” is the sum of bits to be set. For example, when

setting bits 2 and 1 to “1”, “Y” becomes “6”.

Fig. 2 How to write data in oscillation circuit control register 1 (indentical with Figure 64 in data sheet “M37735MHBXXXFP”)

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