Zilog EZ80F91 Manuel d'utilisateur télécharger pdf (Page 53)

eZ80F91 Development Kit

User Manual

UM014220-0508 eZ80F91 Module

eZ80F91 Module Memory

Static RAM

The eZ80F91 Module features 512 KB of fast SRAM. Access speed is

typically 12 ns, allowing zero-wait-state operation at 50 MHz. With the

CPU at 50 MHz, SRAM can be accessed with zero wait states in eZ80

mode. CS1_CTL (CS1

) can be set to 08h (no wait states).

Flash Memory

The eZ80F91 Module features 256 KB of on-chip Flash memory, which

can be programmed a single byte at a time, or in bursts of up to 128 bytes.

Write operations can be performed using either memory or I/O instruc-

tions. Erasing bytes in Flash memory returns them to a value of

FFh. Both

the MASS ERASE and PAGE ERASE operations are self-timed by the

Flash controller, leaving the CPU free to execute other operations in par-

allel. Upon power-up, the on-chip Flash memory is located in the address

range

000000h–03FFFFh. Four wait states are programmed in Flash

control register F8h.

On-chip Flash memory is prioritized over all external Chip Selects, can be

enabled or disabled (power-on enabled), and can be programmed within

any 256 KB address space in the 16 MB address range.

The eZ80F91 Module features the following memory configurations:

•

On-chip SRAM: 8 KB

•

Off-chip SRAM: 512 KB

•

On-chip Flash: 256 KB

Reset Generator

An onboard supervisory chip is connected to the eZ80F91 Reset input

pin. It performs reliable Power-On Reset functions, generating a reset

pulse with a duration of 200 ms if the power supply drops below 2.93 V.

This reset pulse ensures that the board always starts in a defined

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Zilog EZ80F91 Manuel d'utilisateur Page 53