GDC21D301A datasheet(27/35 Pages) HYNIX

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GDC21D301A

PSI_n’ s data Buffer End Pointer Register (0x61a+ 4*N)

Same as Start pointer register. But the real end

address of data buffer is one less than this register

value, for example, the real end address of PSI_4

data buffer is equal to 0x61b which is calculated by

‘0x61c minus 0x001’. The buffer size is calculated

by the following.

Size = End Pointer - Start Pointer.

PSI_n’ s data Buffer Read Pointer Register (0x61c + 4*N)

Actually this register is not used. In order to read

data in this buffer, you should access local DRAM

directly like accessing internal register.

1) When M16 = ‘ 1’ (16Mbit DRAM used)

When it is ‘Write’, the lower 6 bits are written to

, and the value should be

located between

start

and end pointer. It is recommended that the initial

value is the same of the start pointer. When ‘Read’,

the lower 16 bits are read.

Internal Read Pointer Register

2) When M16 = ‘ 0’ (4Mbit DRAM used)

When it is ‘Write’, the lower 4 bits and higher 2

bits are written to ‘0’, and the value should be

located between start and end pointer. It is

recommended that this initial value is the same of

start pointer value. When ‘Read’, the lower 16 bits

are read.

Internal Read Pointer register

When ‘ Write’

When ‘ Read’

16 15

When ‘ Write’

When ‘ Read’

20 19

16 15

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