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Jennic

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Jennic

4.1 ROM

The ROM is 192K bytes in size, organized as 48k x 32-bit words and can be accessed by the CPU in a single clock

cycle. The ROM contents include bootloader to allow external Flash memory contents to be bootloaded into RAM at

runtime, a default interrupt vector table, an interrupt manager, IEEE802.15.4 MAC and assorted APIs for interfacing

to the MAC and on-chip hardware peripherals. The operation of the boot loader is described in detail in Application

Note JN-AN-1003 Boot Loader Operation [2]. The interrupt manager routes interrupt calls to the application’s soft

interrupt vector table contained within RAM. Section 7 contains further information regarding the handling of

interrupts. Typical ROM contents are shown in Figure 6.

0x0002FFFF

0x00000000

Unused

APIs

IEEE802.15.4 MAC

Boot Loader

Interrupt Manager

Interrupt Vectors

Figure 6: ROM contents

4.2 RAM

The JN5139 contains 96k bytes of high speed RAM organized as 24k x 32-bit. It can be used for both code and data

storage and is accessed by the CPU in a single clock cycle. At reset, a boot loader controls the loading of segments

of code and data from an external memory connected to the SPI port, into RAM. Software can control the power

supply to the RAM allowing the contents to be maintained during a sleep period when other parts of the device are

un-powered. Typical RAM contents are shown in Figure 7.

2k Bytes

92k Bytes

4K Bytes

24 Bytes

12 Bytes

32 Bytes

0x04018000

0x04017800

0x04001020

0x04000000

0x04000FD0

0x04000FF4

0x04001000

CPU Stack (Grows down)

Application

Networking Stack

MAC Address

OAD Data

FLASH Header Data

MAC Data

Interrupt Vector Table

Figure 7: RAM Contents