Rainbow Electronics ATmega128L - Manual (Page 314)

314
ATmega128(L)
2467B–09/01
5. This requirement applies to all ATmega128 2-wire Serial Interface operation. Other
devices connected to the 2-wire Serial Bus need only obey the general f
SCL
requirement.
6. The actual low period generated by the ATmega128 2-wire Serial Interface is (1/f
SCL
-
2/f
CK
), thus f
CK
must be greater than 6 MHz for the low time requirement to be strictly
met at f
SCL
= 100 kHz.
7. The actual low period generated by the ATmega128 2-wire Serial Interface is (1/f
SCL
-
2/f
CK
), thus the low time requirement will not be strictly met for f
SCL
> 308 kHz when
f
CK
= 8 MHz. Still, ATmega128 devices connected to the bus may communicate at full
speed (400 kHz) with other ATmega128 devices, as well as any other device with a
proper t
LOW
acceptance margin.
Figure 153. 2-wire Serial Bus Timing
SPI Timing
Characteristics See Figure 154 and Figure 155 for details.
t
SU;STA
t
LOW
t
HIGH
t
LOW
t
of
t HD;STA t HD;DAT t SU;DAT
t SU;STO
t BUF
SCL
SDA
t r
Table 136. SPI Timing Parameters
Description Mode Min Typ Max
1 SCK period Master See Table 72
ns
2 SCK high/low Master 50% duty cycle
3 Rise/Fall time Master TBD
4 Setup Master TBD
5 Hold Master TBD
6 Out to SCK Master TBD
7 SCK to out Master TBD
8 SCK to out high Master TBD
9 SS low to out Slave TBD
10 SCK period Slave 4 • t
ck
TBD
11 SCK high/low Slave 2 • t
ck
TBD
12 Rise/Fall time Slave TBD
13 Setup Slave TBD
14 Hold Slave TBD
15 SCK to out Slave TBD
16 SCK to SS high Slave TBD
17 SS high to tri-state Slave TBD