Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet
Product codes
ATSAM4S-WPIR-RD
SAM4S Series [DATASHEET]
Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14
420
24.
Boot Program
24.1
Description
The SAM-BA
Boot Program integrates an array of programs permitting download and/or upload into the different
memories of the product.
24.2
Hardware and Software Constraints
SAM-BA Boot uses the first 2048 bytes of the SRAM for variables and stacks. The remaining available size
can be used for user's code.
USB Requirements:
̶
External Crystal or External Clock
with frequency of:
11,289 MHz
12,000 MHz
16,000 MHz
18,432 MHz
UART0 requirements: None
Note:
1. Must be 2500 ppm and 1.2V Square Wave Signal.
24.3
Flow Diagram
Figure 24-1.
Boot Program Algorithm Flow Diagram
The SAM-BA Boot program seeks to detect a source clock either from the embedded main oscillator with external
crystal (main oscillator enabled) or from a supported frequency signal applied to the XIN pin (Main oscillator in
bypass mode).
If a clock is found from the two possible sources above, the boot program checks to verify that the frequency is one
If a clock is found from the two possible sources above, the boot program checks to verify that the frequency is one
of the supported external frequencies. If the frequency is one of the supported external frequencies, USB
activation is allowed, else (no clock or frequency other than one of the supported external frequencies), the internal
Table 24-1.
Pins Driven during Boot Program Execution
Peripheral
Pin
PIO Line
UART0
URXD0
PA9
UART0
UTXD0
PA10
Device
Setup
Character # received
from UART0?
Run SAM-BA Monitor
USB Enumeration
Successful ?
Yes
Run SAM-BA Monitor
Yes
No
No