ez80190 ZiLOG Semiconductor, ez80190 Datasheet - Page 162

• Manufacturer Part Number: ez80190
• Description: Ez80190 Microprocessor
• Manufacturer: ZiLOG Semiconductor

PS006613-0306
ZDI START Condition
ZCL
ZDA
ZCL
ZDA
All ZDI commands are preceded by the ZDI START signal, which is a High-to-Low
transition of ZDA when ZCL is High. The ZDI slave on the eZ80190 device contin-
ually monitors the ZDA and ZCL lines for the START signal and does not respond
to any command until this condition is met. The master pulls ZDA Low, with ZCL
High, to indicate the beginning of a data transfer with the ZDI block. Figures 28
and 29 illustrate a valid ZDI START signal prior to writing and reading data,
respectively. A Low-to-High transition of ZDA while the ZCL is High produces no
effect.
Data is shifted in during a write to the ZDI block on the rising edge of ZCL, as illus-
trated in
ing edge of ZCL, as illustrated in
master stops during the ninth cycle and holds the ZCL signal High.
Start Signal
Start Signal
Figure
28. Data is shifted out during a read from the ZDI block on the fall-
Change
Change
ZDA
ZDA
Figure 28. ZDI Write Timing
Figure 29. ZDI Read Timing
ZDI Data In
(write)
PRELIMINARY
Stable
Stable
ZDA
ZDA
ZDI Data Out
Figure
(read)
Change
Change
ZDA
ZDA
29. When an operation is completed, the
ZDI Data In
(write)
eZ80190 Product Specification
Stable
Stable
ZDA
ZDA
ZDI Data Out
(read)
Change
Change
ZDA
ZDA
ZiLOG Debug Interface
148