MC9328MX21_06 Datasheet, PDF (22/98 Pages) Freescale Semiconductor, Inc – i.MX family of microprocessors

Specifications
3.8.1.1.2 MMD Write BMI Timing
Figure 7 shows the MMD write BMI timing when MMD drives clock. On each falling edge of BMI_CLK/
CS BMI checks the BMI_WRITE logic level to determine if the current cycle is a write cycle. If the BMI_
WRITE is logic low, it latches data into the RxFIFO on each falling edge of BMI_CLK/CS signal.
BMI_CLK/CS
BMI_READ_REQ
Can be asserted any time
Can be asserted any time
BMI_D[15:0]
BMI_WRITE
RxD1 RxD2
Tds
Last RxD
Ts
Th
Figure 7. MMD (ATI) Drives Clock, MMD Write BMI Timing
(MMD_MODE_SEL=1, MASTER_MODE_SEL=0, MMD_CLKOUT=0)
Table 15. MMD Write BMI Timing
Item
write setup time
write hold time
receive data setup time
Symbol Minimum Typical Maximum
Unit
Ts
11
–
Th
0
–
Tds
5
–
–
ns
–
ns
–
ns
Note: All timings assume that the hclk is running at 133 MHz.
Note: At this mode, the maximum frequency of the BMI_CLK/CS can be up to 36 MHz (doubles as maximum data pad speed).
3.8.1.2 BMI Drives the BMI_CLK/CS
In this mode MMD_MODE_SEL and MMD_CLKOUT are both set. The software must know which
mode it is now (READ or WRITE). When the BMI_WRITE is high, BMI drives BMI_CLK/CS out if the
TxFIFO is not emptied. When BMI_WRITE is low, user can write a 1 to READ bit of control register1 to
issue a write cycle (MMD write BMI).
3.8.1.3 MMD Read BMI Timing
Figure 13 shows the MMD read BMI timing when BMI drives the BMI_CLK/CS. When the BMI_WRITE
is high, the BMI drives BMI_CLK/CS out if data is written to TxFIFO (BMI_READ_REQ become high),
BMI puts data into data bus and enable data out on the rising edge of BMI_CLK/CS. The MMD devices
can latch the data on each falling edge of BMI_CLK/CS.
It is recommended that the MMD do not change the BMI_WRITE signal from high to low when the
BMI_READ_REQ is asserted. If user writes data to the TxFIFO when the BMI_WRITE is low, the BMI
will drive BMI_CLK/CS out once the BMI_WRITE is changed from low to high.
MC9328MX21 Technical Data, Rev. 3.1
22
Freescale Semiconductor