Cirrus Logic CS8900A - Manual (Page 110)

110 DS271F5
CS8900A
Crystal LAN™ Ethernet Controller
CIRRUS LOGIC PRODUCT DATASHEET
ENTER BOUNDARY SCAN:
CS8900A resets, all digital
output pins and bi-directional
pins enter High-Z state,
and AEN becomes shift clock
AEN switches high
OUTPUT CYCLE
AEN switches low
Selected output
goes low
AEN switches high
34 cycles
INPUT CYCLE
AEN switches low
Selected input
copied out
to the
EEDataOut
pin
AEN switches high
50 cycles
All digital output pins and
bi-directional pins enters
High-Z state
TEST switches low (AEN must be low)
Not in Boundary Scan
Test Mode
AEN switches low
AEN switches high
EXIT BOUNDARY SCAN:
AEN becomes ISA bus
Address Enable
TEST switches high
Figure 32. Boundary Scan Continuity Cycle