MC68341UMAD Datasheet, PDF (14/21 Pages) Motorola, Inc – Integrated Processor Users Manual

51. Single Address Enable
6-33 SE-Single Address Enable: The note “used for intermodule DMA” should be for the SE=1 case. The
68341 does not support intermodule single address transfers, so the SE bit should always be programmed to
“0”.
52. Code Examples - Immediate Addressing Mode
On pages 6-40 through 6-44 make the following change as shown for each occurrence of SARADD, DARADD,
and NUMBYTE (change to immediate addressing mode for source operand):
MOVE.L SARADD,DMASAR1(A0) should be MOVE.L #SARADD,DMASAR1(A0).
MOVE.L DARADD,DMADAR1(A0) should be MOVE.L #DARADD,DMADAR1(A0).
MOVE.L NUMBYTE,DMABTC1(A0) should be MOVE.L #NUMBYTE,DMABTC1(A0).
53. Serial Oscillator Problems with DMA activity
Add to the Crystal Input or External Clock (X1) section on page 7-5: A high DREQ1 request rate (greater than
1MHz) with excessive undershoot on DREQ1 can result in internal signal coupling to the serial module oscil-
lator X1 pin, damping out oscillation. Avoid routing DREQ1 near the serial oscillator external components, and
use termination techniques such as series termination of the DREQ1 driver (start with 33Ω) to limit edge rate
of the signal and accompanying undershoot.
54. Additional Note on RTSx operation details
Add to the RTSA and RTSB descriptions on page 7-6: The RTSx outputs are active low signals - they drive a
logic “0” when set, and a logic “1” when cleared.
RTSx can be set (output logic level 0) by any of the following:
• Writing a “1” to the corresponding bit in the OPSET register $71E
• Issuing an “Assert RTS” command using command register CR
• If RxRTS=1, set by receiver FIFO transition from FULL to not-FULL
RTSx can be cleared (output logic level 1) by any of the following:
• Hardware reset of the serial module
• Writing a “1” to the corresponding bit in the OPRESET register $71F
• Issuing a “Negate RTS” command using command register CR
• If RxRTS=1, cleared by receiver FIFO transition from not-FULL to FULL
• If TxRTS=1, cleared by completion of last character, including transmission of stop bits
55. Serial Frequency Restriction
On page 7-8, place the following notes at the end of Section 7.3.1 Baud Rate Generator:
The current implementation of the serial module restricts the minimum CLKOUT frequency at which the baud
rate generators can be used to approximately 8.3MHz. Operation below this frequency results in a synchro-
nized internal clock which is at a lower frequency than the X1 input, which then results in incorrect baud rates.
One method to extend the minimum CLKOUT frequency is to reduce the X1 frequency by powers of 2 as
shown in the table below. The corresponding baud rates selected by the clock select register programming are
MOTOROLA
MC68341 USER’S MANUAL ADDENDUM
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