XA-H4 Datasheet, PDF(31/42 Page) NXP Semiconductors – Single-chip 16-bit microcontroller

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XA-H4 Datasheet, PDF (31/42 Pages) NXP Semiconductors – Single-chip 16-bit microcontroller

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Philips Semiconductors

Single-chip 16-bit microcontroller

Preliminary specification

XA-H4

8. tRP is specified as the minimum high time (thus inactive) on each of the 5 individual CS_RAS[5:1] pins when such pin is programmed in the

memory controller to service DRAM. The number of CClks (system clocks) in tRP is programmable, and is represented by n in the tRP

equation in the AC tables. Regardless of what value is programmed into the control register, n will never be less than 2 clocks. Thus, at

30 Mhz system clock, the minimum value for RAS precharge is tRP=((2 * tC) â 16= ((2 * 33.33) â 16) = 50.6 ns. As the system clock

frequency FC, is slowed down, tC (system clock period) of course becomes greater, and thus tRP becomes greater.

9. The MIN value for this parameter is guaranteed by design and is not tested in production to the specified limit. In those cases where a

maximum value is specified in the table for this parameter, it is tested.

TIMING DIAGRAMS

All references to numbered Notes are to the notes following the AC Electrical Characteristics tables

ClkOut

A19âA1

BHE/BLE

tCHAV

tAVSL

tCHSL

tCHAH

tAHDR

(Does Not Include A0)

tCHSH

D15âD0

Note 3

tDIH (Note 2)

tDIS

Note: On Generic Data Reads, A0 can terminate a full clock period before A19âA1, and therefore

should not be used on some peripheral devices.

Figure 7. Generic (SRAM, ROM, Flash, I/O Devices, etc.) Read on 16-Bit Bus

SU01277

1999 Sep 24

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