Basic Configuration; Functional Description; Figure 6.6-2 Descriptor Table Entry Structure - Nuvoton ISD94124BYI Technical Reference Manual

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Basic Configuration

Clock source configuration

Enable PDMA controller clock in PDMACKEN (CLK_AHBCLK [1]).

Reset configuration

Reset PDMA controller in PDMARST (SYS_IPRST0[2]).

The PDMA controller transfers data from one address to another without CPU intervention. The

PDMA controller supports 16 independent channels and serves only one channel at one time, as

the result, PDMA controller supports two level channel priorities: fixed and round-robin priority,

PDMA controller serves channel in order from highest to lowest priority channel. The PDMA

controller supports two operation modes: Basic mode and Scatter-gather mode. Basic mode is used

to perform one descriptor table transfer. Scatter-gather mode has more entries for each PDMA

channel, and thus the PDMA controller supports sophisticated transfer through the entries. The

descriptor table entry data structure contains many transfer information including the transfer

source address, transfer destination address, transfer count, burst size, transfer type and operation

mode. The Figure 6.6-2 shows the diagram of descriptor table (DSCT) data structure.

PDMA controller also supports single and burst transfer type and the request source can be from

software or peripheral request, transfer between memory to memory using software request. A

single transfer means that software or peripheral is ready to transfer one data (every data needs

one request), and the burst transfer means that software or peripherals will transfer multiple data

(multiple data only need one request).

Channel Priority

The PDMA controller supports two level channel priorities including fixed and round-robin priority.

The fixed priority channel has higher priority than round-robin priority channel. If multiple channels

are set as fixed or round-robin priority, the higher channel will have higher priority. The priority order

ISD94100 Series Technical Reference Manual

Descriptor Table Entry Structure

Descriptor Table

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