EDOSK2674 Datasheet, PDF (21/41 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

The user may replace the HC49/U surface mounted AT cut crystal with another of similar type within the operating frequency
of the MCU device. Please refer to the hardware manual for the MCU for the valid operating range.
Another crystal is provided at 16 x 115200 (1.8432MHz). This crystal output is fed directly into the SCK2 pin of the MCU
allowing, with correct register settings, a fixed serial baud rate of 115200bps with zero errors.
The user may wish to ignore the serial clock oscillator input and use the system clock for baud rate generation – register
settings will need to be amended as per the following example.
Example:
The following table shows the baud rates and Baud Rate Register (BRR) setting required for each communication rate using
the operating speed of 33.0000MHz (default). Note that there are no zero error percentages.
Baud Rate Register Settings for Serial Communication Rates using 33.0000MHz system clock
SMR Setting:
0
1
2
3
Comm.
Baud
110
300
1200
2400
4800
9600
19200
38400
57600
115200
BRR
setting
Invalid
Invalid
Invalid
Invalid
214
106
53
26
17
8
ERR (%)
Invalid
Invalid
Invalid
Invalid
0.07
0.39
0.54
0.54
0.54
0.54
BRR
setting
Invalid
Invalid
214
106
53
26
12
6
3
1
ERR (%)
Invalid
Invalid
0.07
0.39
0.54
0.54
3.29
4.09
11.90
11.90
BRR
setting
Invalid
214
53
26
12
6
2
1
0
0
ERR (%)
Invalid
0.07
0.54
0.54
3.29
4.09
11.90
16.08
11.90
44.05
BRR
setting
145
53
12
6
2
1
0
Invalid
Invalid
Invalid
ERR (%)
0.33
0.54
3.29
4.09
11.90
16.08
16.08
Invalid
Invalid
Invalid
TABLE 4-1 CRYSTAL FREQUENCIES FOR RS232 COMMUNICATION
4.5. REMOVABLE COMPONENT INFORMATION.
Analogue and reference voltages to the MCU are, as default, isolated from the Auxiliary I/O connector by not fitted 0805
resistors. To make this connection the following resistors must be removed and re-soldered or replaced in the alternative
positions detailed below:
H8/2674R pin
Remove
Fit
Resistor Value
AVCC (pin 122)
R25
R9
0Ω, 0805
AVSS (pin 131)
R7
R8
0Ω, 0805
VREF (pin 121)
R11
R10
0Ω, 0805
Care must be taken not to damage the tracking around these components. Only use soldering equipment designed for
surface mount assembly and rework.
4.6. ADDITIONAL COMPONENT INFORMATION.
The addition of a 0Ω resistor fitted in position R37 will permanently deactivate the Main Flash. This is to be used when CS0n
and/or CS1n are to be used by an Expansion Board.
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