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Introduction

This Technical Note describes the differences in procedure when loading Flash memory on Zilog’s

Z8F640x and Z8F64xx microcontroller units (MCU). The Z8F64xx MCUs, which evolved from the

Z8F640x MCUs, offer better Flash protection and flexibility features by comparison.

General Overview of Z8 Encore! XP

Flash Memory

The Z8F640x and Z8F64xx MCU families each feature 64 KB (65,536 bytes) of non-volatile Flash

memory with read, write, and erase capability. Flash memory can be programmed and erased

in-circuit by either user code or through the On-Chip Debugger. The Flash memory array is arranged

as 512 bytes per page. A 512 bytes page is the minimum Flash block size that can be erased.

Flash Information Area

The Z8F64xx MCUs feature a 512 bytes Information Area, which is accessed by setting bit 7 of the

Flash Page Select Register to 1. When access is enabled, the Information Area is mapped into

Program Memory and overlays the 512 bytes in the address range

FE00h–FFFFh. When access to the

Information Area is enabled, a code instruction returns data from the Information Area. CPU

instructions are always fetched from Program Memory regardless of the setting of the Information

Area access bit. Access to the Information Area is Read-Only.

Table 1 describes the functions of each range of Program Memory addresses in the Z8F64xx MCU’s

Information Area.

The Z8F640x MCUs do not feature an Information Area.

Table 1. Z8F64xx Information Area Map

Program Memory Address (Hex) Function

FE00h–FE3Fh Reserved.

FE40h–FE53h Part Number—20 character ASCII alphanumeric code;

left-justified and filled with zeroes.

FE54h–FFFFh Reserved.

Note:

Technical Note

Comparing Z8 Encore! XP

F640x and

Z8 Encore! XP

F64xx Flash Loaders

TN003003-0308

TN003003-0308 Page 2 of 15

Comparing Z8 Encore! XP

F640x and Z8 Encore! XP

F64xx Flash

Loaders

Table 2 compares the Flash memory spaces of the Z8F640x MCU and the Z8F64xx MCU.

Table 3 compares the Flash address ranges of the Z8F640x MCU and the Z8F64xx MCU by sector.

Z8 Encore! XP

Flash Control Register Descriptions

There are a number of registers available in the Z8 Encore! XP MCU that provide access to Flash

memory. They are briefly described in this section.

Flash Control Register

The Flash Control Register (FCTL) unlocks the Flash Controller for programming and erase

operations. It also selects the Flash Sector Protect register on the Z8F64xx MCU. The Write-Only

Flash Control Register shares its register file address space with the Read-Only Flash Status Register.

Table 2. Flash Memory Configurations for Z8F640x and Z8F64xx MCUs

Z8 Encore!

XP MCU

Total Size of

Flash Memory

Number

of Pages

Program Memory

Addresses

Number

of Sectors

Pages

per

Sector

Size of Each

Sector

Z8F640x 64 KB (65,536) 128 0000h–FFFFh 1 16 8 KB (8192)

Z8F64xx 64 KB (65,536) 128 0000h–FFFFh 8 16 8 KB (8192)

Table 3. Flash Sector Address Ranges

Sector Number Z8F640x MCUs Z8F64xx MCUs

0 NA 0000h–1FFFh

1 NA 2000h–3FFFh

2 NA 4000h–5FFFh

3 NA 6000h–7FFFh

4 NA 8000h–9FFFh

5 NA A000h–BFFFh

6 NA C000h–DFFFh

7 E000h–FFFFh

(High Sector)

E000h–FFFFh