MT90225AG Zarlink Semiconductor, MT90225AG Datasheet - Page 73

• Manufacturer Part Number: MT90225AG
• Description: Description = 16 Port TC PHY For T1, E1 And DSL ;; Package Type = N/a ;; No. Of Pins =
• Manufacturer: Zarlink Semiconductor

MT90225/226
Data Sheet
9.1 CPU Interface Timing
The CPU Interface of the MT90225/226 supports both the Motorola and Intel timing modes. No Mode Select pin is
required.
With Motorola devices, the Motorola R/W-signal is connected to the UP_R/W pin and the UP_OE pin is tied to
ground. There is no DS signal and the UP_CS signal is taken to access the MT90225/226.
When used with Intel devices, the READ-signal is connected to the UP_OE pin and the WRITE-signal is connected
to the UP_R/W pin.
When performing a read operation, data is placed on the bus immediately after UP_CS is LOW UP_R/W is HIGH
for the Motorola timing mode and after the UP_CS and UP_OE signals are LOW for Intel timing.
When performing a write operation in Motorola timing mode, the data is clocked into an MT90225/226 pre-load
register on the rising edge of the UP_R/W or UP_CS signal. In Intel timing mode, the data is clocked into
MT90225/226 pre-load register on the rising edge of the UP_R/W or UP_CS signal. Right after that transition, the
data is transferred to the MT90225/226’s internal register. Writing data into this register can take up 2 system clock
cycles.
Zarlink Semiconductor Inc.
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