3804H_M Datasheet, PDF (29/387 Pages) Renesas Technology Corp – 8-BIT CISC SINGLE-CHIP MICROCOMPUTER 740 FAMILY / 38000 SERIES

3804 Group (Spec.H)
[CPU Mode Register (CPUM)] 003B16
The CPU mode register contains the stack page selection bit, etc.
The CPU mode register is allocated at address 003B16.
HARDWARE
FUNCTIONAL DESCRIPTION
b7
1
Fig. 8 Structure of CPU mode register
b0
CPU mode register
(CPUM : address 003B16)
Processor mode bits
b1 b0
0 0 : Single-chip mode
0 1:
1 0 : Not available
1 1:
Stack page selection bit
0 : 0 page
1 : 1 page
Fix this bit to “1”.
Port XC switch bit
0 : I/O port function (stop oscillating)
1 : XCIN–XCOUT oscillating function
Main clock (XIN–XOUT) stop bit
0 : Oscillating
1 : Stopped
Main clock division ratio selection bits
b7 b6
0 0 : φ = f(XIN)/2 (high-speed mode)
0 1 : φ = f(XIN)/8 (middle-speed mode)
1 0 : φ = f(XCIN)/2 (low-speed mode)
1 1 : Not available
Rev.1.00 Jan 14, 2005
REJ09B0212-0100Z
1-11