Download ECP Standard Parallel Interface for DSP56300 Devices

3.2.1 ECP Forward Data Cycle
In the forward data cycle, the host sends a single byte of compressed data to the peripheral. This cycle
consists of six steps:
1. Host places data on data lines.
2. Host asserts HostAck to indicate the start of a data cycle.
3. Host asserts HostClk to low to indicate valid data.
4. Peripheral asserts PeriphAck to acknowledge valid.
5. Host deasserts HostClk high. The +ve edge is used to shift data into the peripheral.
6. Peripheral de-asserts PeriphAck to acknowledge receiving the byte.
These steps are illustrated in Figure 1.
HostClk
PeriphAck
HostAck
Data
Figure 1. ECP Forward Data Cycle
3.2.2 ECP Forward Command Cycle
In the forward command cycle, the host sends a channel address to the peripheral. This cycle consists of six
steps:
1. Host places data on data lines.
2. Host deasserts HostAck to indicate the start of a command cycle.
3. Host asserts HostClk low to indicate valid data.
4. Peripheral asserts PeriphAck to acknowledge valid data.
5. Host deasserts HostClk high. The +ve edge is used to shift data into the peripheral.
6. Peripheral deasserts PeriphAck to acknowledge receiving the byte.
These steps are illustrated in Figure 2.
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ECP Standard Parallel Interface for DSP56300 Devices