M37542F8FP Renesas Electronics America, M37542F8FP Datasheet - Page 18

• Manufacturer Part Number: M37542F8FP
• Description: IC 740 MCU FLASH 32K 36SSOP
• Manufacturer: Renesas Electronics America
• Series: 740/38000r

Specifications of M37542F8FP

• Core Processor: 740
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: SIO, UART/USART
• Peripherals: POR, WDT
• Number Of I /o: 29
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: FLASH
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 85°C
• Package / Case: 36-SSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

7542 Group
[CPU mode register] CPUM
The CPU mode register contains the stack page selection bit, etc..
This register is allocated at address 003B
Switching method of CPU mode register
Switch the CPU mode register (CPUM) at the head of program af-
ter releasing Reset in the following method.
Fig. 14 Switching method of CPU mode register
Rev.3.03
REJ03B0006-0303
Jul 11, 2008
selection bits (bits 6 and 7 of CPUM)
Wait by on-chip oscillator operation
until establishment of oscillator clock
Note: After system is released from reset, an on-chip oscillator turns active automatically
Switch the clock division ratio
selection bit (bit 5 of CPUM)
Switch the oscillation mode
and system operation is started.
After releasing reset
Page 16 of 117
Main routine
16
.
Select 1/1, 1/2, 1/8 or on-chip oscillator.
When using a ceramic oscillation, wait until
establlishment of oscillation from oscillation starts.
When using an RC oscillation, wait time is not
required basically (time to execute the instruction to
switch from an on-chip oscillator meets the
requirement).
An initial value is set as a ceramic
oscillation mode. When it is switched to an
RC oscillation, its oscillation starts.
Start with an on-chip oscillator
Fig. 13 Structure of CPU mode register
b7
Note 1: These bits can be rewritten only once after releasing reset. After rewriting
2: These bits are used only when a ceramic oscillation is selected.
Do not use these when an RC oscillation is selected.
it is disable to write any data to bits. However, by reset bits are
initialized and can be rewritten, again.
(It is not disable to write any data to bits for emulator MCU
“M37542RSS”.)
b0
CPU mode register
(CPUM: address 003B
Processor mode bits (Note 1)
Stack page selection bit
Oscillation mode selection bit (Note 1)
On-chip oscillator oscillation control bit
X
Clock division ratio selection bits
IN
b1 b0
b7 b6
0
0
1
1
0 : 0 page
1 : 1 page
0 : On-chip oscillator oscillation enabled
1 : On-chip oscillator oscillation stop
0 : Ceramic oscillation
1 : RC oscillation
0
0
1
1
0 : Ceramic or RC oscillation enabled
1 : Ceramic or RC oscillation stop
oscillation control bit
0 Single-chip mode
1
0
1
0 : f(φ) = f(X
1 : f(φ) = f(X
0 : applied from on-chip oscillator
1 : f(φ) = f(X
Not available
16
IN
IN
IN
, initial value: 80
)/2 (High-speed mode)
)/8 (Middle-speed mode)
) (Double-speed mode)(Note 2)
16
)