Motorola MC68341 User Manual page 9

25. Additional Note on PORTA/B Output Timing
Add to the External Bus Interface Operation description on page 4-17: The Port A and Port B output pins tran-
sition after the S4 falling edge for the internal write to the respective data register. This places port pin transi-
tions at roughly the same time DS negates for the data register write - note this output delay is not currently
specified in the Electrical Specifications.
26. RTC Memory Map
The RTC register offsets shown on page 4-21 are incorrect - a corrected memory map is shown below. Ad-
dresses within the RTC can be accessed as either bytes or words, with the exception of the reserved byte at
offset $0CE. Note that RTC registers marked S/U are read/write in supervisor mode, but can only be read in
user mode.
ADDR FC
0C0 S
0C2 S/U MINUTES (MIN)
0C4 S/U DATE
0C6 S/U MONTH
0C8 S RTC CONTROL/STATUS (RCR)
0CA S/U MINUTES ALARM (MINA)
0CC S/U DATE ALARM (DATEA)
0CE - RESERVED
27. MBAR Register Reset Values
On page 4-22, the reset values for MBAR bits 31-12 are undefined.
28. MBAR AS7 Bit and IACK Cycles
On page 4-23, the second code sequence initializes the MBAR register with AS7 set. This prevents the ad-
dress decode for the internal 4K register block from responding to CPU space accesses. In particular, it pre-
vents the register block decode of $FFFFFxxx from interfering with IACK cycles (address $FFFFFFFx), and
possibly corrupting the vector number returned. Normal interrupt acknowledge operation for the internal mod-
ules is not affected by this change.
Early versions of the MC68330 User's Manual (original release) and MC68340 User's Manual (original and
Rev. 1 releases) did not show AS7 set. Code which was developed based on these manual revisions should
be checked for this problem when porting to the MC68341 - this change should also be applied back to the
MC68330 and/or MC68340.
29. Additional Note on VCO Overshoot
On page 4-30 place the following note under the Y-bits description:
MOTOROLA
15
RTC INTERRUPT CONTROL (RICR)
MC68341 USER'S MANUAL ADDENDUM
8 ADDR FC 7
0C3 S/U SECONDS (SEC)
0C5 S/U HOUR
0C7 S/U YEAR
0C9 S/U DAY
0CB S/U SECONDS ALARM (SECA)
0CD S/U HOURS ALARM (HOURA)
0CF S RTC CALIBRATION (RCCR)
0
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