Please check the following:
1) Is each power supply supplied correctly?
2) Is the correct potential applied?
3) Are clocks input to SH-3?
4) Are the conditions and timing of the power-on reset correct?
5) SH-3 is not initialized by a manual reset.
A power-on reset must always be performed when powering on.
6) Is the SH7705 MD6 connected (or pulled down) to VssQ?
7) Is MODE<5:0> fixed to each setting level ('High' or 'low')?
8) Does CKIO output expected frequency?
9) Is access to Area0 performed after releasing a power-on reset
(SH-3 accesses to h'a000 0000 when a power-on reset is released.)
10) Is /WAIT negated "High"?
11) CA pin (CA pin must be pulled up externally when hardware standby is not used.)
12) ASEMD0 setting. ASEMD0 must be high when the emulator or H-UDI are not used.
13) Please refer to the following FAQ about SH7705 TRST pin.
14)Please check the status of STATUS[1:0] pin before and after a reset.
STATUS[1:0]=HH: Reset, STATUS[1:0]=LL: Normal operation