JN5148 NXP Semiconductors, JN5148 Datasheet - Page 18

• Manufacturer Part Number: JN5148
• Description: The JN5148 is an ultra low power, high performance MCU combined with an IEEE802
• Manufacturer: NXP Semiconductors

At reset, the contents of this memory are copied into RAM by the software boot loader. The Flash memory devices
that are supported as standard through the JN5148 bootloader are given in Table 1. Jennic recommends that where
possible one of these devices should be selected.
Applications wishing to use an alternate Flash memory device should refer to application note [2] JN-AN-1038
Programming Flash devices not supported by the JN51xx ROM-based bootloader. This application note provides
guidance on developing an interface to an alternate device.
4.4.1 External Memory Encryption
The contents of the external serial memory may be encrypted. The AES security processor combined with a user
programmable 128-bit encryption key is used to encrypt the contents of the external memory. The encryption key is
stored in eFuse.
When bootloading program code from external serial memory, the JN5148 automatically accesses the encryption key
to execute the decryption process. User program code does not need to handle any of the decryption process; it is
transparent.
With encryption enabled, the time taken to boot code from external flash is increased.
4.5 Peripherals
All peripherals have their registers mapped into the memory space. Access to these registers requires 3 clock
cycles. Applications have access to the peripherals through the software libraries that present a high-level view of
the peripheral’s functions through a series of dedicated software routines. These routines provide both a tested
method for using the peripherals and allow bug-free application code to be developed more rapidly. For details, see
the JN51xx Integrated Peripherals API User Guide (JN-UG-3066)[5].
4.6 Unused Memory Addresses
Any attempt to access an unpopulated memory area will result in a bus error exception (interrupt) being generated.
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Manufacturer
SST (Silicon Storage Technology)
Numonyx
Table 1: Supported Flash Memories
JN-DS-JN5148-001 1v7
Device Number
25VF010A (1Mbit device)
M25P10-A (1Mbit device),
M25P40 (4Mbit device)
© NXP Laboratories UK 2011