MC94MX21 Datasheet, PDF (62/98 Pages) Freescale Semiconductor, Inc – 333 and 350 MHz

Specifications
3.19 External Interface Module (EIM)
The External Interface Module (EIM) handles the interface to devices external to the i.MX21, including
generation of chip-selects for external peripherals and memory. The timing diagram for the EIM is shown
in Figure 53, and Table 42 defines the parameters of signals.
(HCLK) Bus Clock
Address
Chip-select
Read (Write)
OE (rising edge)
OE (falling edge)
EB (rising edge)
EB (falling edge)
1a
2a
3a
4a
4c
5a
5c
1b
2b
3b
4b
4d
5b
5d
LBA (negated falling edge)
LBA (negated rising edge)
Burst Clock (rising edge)
Burst Clock (falling edge)
Read Data
Write Data (negated falling)
Write Data (negated rising)
DTACK
6a
6a
7a
7c
9a
9a
10a
6b
6c
7b
11
7d
8b
8a
9b
9c
10a
Figure 53. EIM Bus Timing Diagram
MC94MX21 Technical Data, Rev. 1.4
62
Freescale Semiconductor