3804H Datasheet, PDF (67/116 Pages) Renesas Technology Corp – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

3804 Group (Spec. H)
[I²C START/STOP Condition Control Register
(S2D)] 001616
The I²C START/STOP condition control register (S2D: address
001616) controls START/STOP condition detection.
•Bits 0 to 4: START/STOP condition set bits (SSC4–SSC0)
SCL release time, setup time, and hold time change the detection
condition by value of the main clock divide ratio selection bit and
the oscillation frequency f(XIN) because these time are measured
by the internal system clock. Accordingly, set the proper value to
the START/STOP condition set bits (SSC4 to SSC0) in considered
of the system clock frequency. Refer to Table 11.
Do not set “000002” or an odd number to the START/STOP condi-
tion set bits (SSC4 to SSC0).
Refer to Table 12, the recommended set value to START/STOP
condition set bits (SSC4–SSC0) for each oscillation frequency.
•Bit 5: SCL/SDA interrupt pin polarity selection bit (SIP)
An interrupt can occur when detecting the falling or rising edge of
the SCL or SDA pin. This bit selects the polarity of the SCL or SDA
pin interrupt pin.
•Bit 6: SCL/SDA interrupt pin selection bit (SIS)
This bit selects the pin of which interrupt becomes valid between
the SCL pin and the SDA pin.
Note: When changing the setting of the SCL/SDA interrupt pin polarity se-
lection bit, the SCL/SDA interrupt pin selection bit, or the I²C-BUS
interface enable bit ES0, the SCL/SDA interrupt request bit may be
set. When selecting the SCL/SDA interrupt source, disable the inter-
rupt before the SCL/SDA interrupt pin polarity selection bit, the SCL/
SDA interrupt pin selection bit, or the I²C-BUS interface enable bit
ES0 is set. Reset the request bit to “0” after setting these bits, and
enable the interrupt.
b7
b0
I²C START/STOP condition
SIS SIP SSC4 SSC3 SSC2 SSC1 SSC0 _{control register}
(S2D : address 001616)
START/STOP condition set bits
SCL/SDA interrupt pin polarity
selection bit
0 : Falling edge active
1 : Rising edge active
SCL/SDA interrupt pin selection bit
0 : SDA valid
1 : SCL valid
Not used
(Fix this bit to “0”.)
Fig. 66 Structure of I²C START/STOP condition control register
Table 12 Recommended set value to START/STOP condition set bits (SSC4–SSC0) for each oscillation frequency
Oscillation
frequency
f(XIN) (MHz)
Main clock
divide ratio
Internal
clock φ
(MHz)
8
2
4
8
8
1
4
2
2
2
2
1
START/STOP
condition
control register
XXX11010
XXX11000
XXX00100
XXX01100
XXX01010
XXX00100
SCL release time
(µs)
6.75 µs (27 cycles)
6.25 µs (25 cycles)
5.0 µs (5 cycles)
6.5 µs (13 cycles)
5.5 µs (11 cycles)
5.0 µs (5 cycles)
Setup time
(µs)
3.5 µs (14 cycles)
3.25 µs (13 cycles)
3.0 µs (3 cycles)
3.5 µs (7 cycles)
3.0 µs (6 cycles)
3.0 µs (3 cycles)
Hold time
(µs)
3.25 µs (13 cycles)
3.0 µs (12 cycles)
2.0 µs (2 cycles)
3.0 µs (6 cycles)
2.5 µs (5 cycles)
2.0 µs (2 cycles)
Note: Do not set an odd number to the START/STOP condition set bits (SSC4 to SSC0) and “000002”.
Rev.1.01 Jan 25, 2005 page 67 of 114
REJ03B0131-0101Z