Digi NS9215 manual A t i c M e m o r y E x t e n d e d W a i t r e g i s t e r, Example, Extw

M E M O R Y C O N T RO L L E R

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Static Memory Extended Wait register. .

S t a t i c M e m o r y E x t e n d e d W a i t r e g i s t e r

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Address: A070 0080

The Static Memory Extended Wait register times long static memory read and write transfers (which are longer than can be supported by the Static Memory Read Delay registers or the Static Memory Write Delay registers) when the EW (extended wait) bit in the related Static Memory Configuration register is enabled.

There is only one Static Memory Extended Wait register, which is used by the relevant static memory chip select if the appropriate EW bit is set in the Static Memory Configuration register.

It is recommended that this register be modified during system initialization, or when there are no current or outstanding transactions. If necessary, however, these control bits can be changed during normal operation.

Register

31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16
							Reserved
15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
		Reserved								EXTW

Register bit

assignment	Bits	Access	Mnemonic	Description
	D31:10	N/A	Reserved	N/A (do not modify)
	D09:00	R/W	EXTW	External wait timeout
				0x0
				16 clock cycles, where the delay is in clk_out cycles
				0x1-0x3FF
				(n=1) x 16 clock cycles
Example
	Static memory read/write time = 16 μs
	CLK frequency = 50 MHz

This value must be programmed into the Static Memory Extended Wait register: (16 x 10-6x 50 x 106 / 16) - 1 = 49

D y n a m i c M e m o r y C o n f i g u r a t i o n 0 – 3 r e g i s t e r s

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Address: A070 0100 / 0120 / 0140 / 0160

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