S912XEP768J5MAGR Freescale Semiconductor, S912XEP768J5MAGR Datasheet - Page 377

• Manufacturer Part Number: S912XEP768J5MAGR
• Description: 16-bit Microcontrollers - MCU 16-bit 768K Flash
• Manufacturer: Freescale Semiconductor

Specifications of S912XEP768J5MAGR

• Rohs: yes
• Core: HCS12X
• Processor Series: MC9S12
• Data Bus Width: 16 bit
• Maximum Clock Frequency: 50 MHz
• Program Memory Size: 768 KB
• Data Ram Size: 48 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 3.3 V to 5 V
• Operating Temperature Range: - 40 C to + 125 C
• Package / Case: LQFP-144
• Mounting Style: SMD/SMT

Figure 10-25
Two concurrent threads are running on the system. One is running on the S12X_CPU and the other is
running on the RISC core. They both have a critical section of code that accesses the same system resource.
To guarantee that the system resource is only accessed by one thread at a time, the critical code sequence
must be embedded in a semaphore lock/release sequence as shown.
Freescale Semiconductor
set_xgsem: 1 is written to XGSEM[n] (and 1 is written to XGSEMM[n])
clr_xgsem: 0 is written to XGSEM[n] (and 1 is written to XGSEMM[n])
ssem:
csem:
gives an example of the typical usage of the XGATE hardware semaphores.
LOCKED BY
clr_xgsem
Executing SSEM instruction (on semaphore n)
Executing CSEM instruction (on semaphore n)
S12X_CPU
ssem &
set_xgsem
Figure 10-24. Semaphore State Transitions
MC9S12XE-Family Reference Manual Rev. 1.25
clr_xgsem
ssem & set_xgsem
UNLOCKED
csem
ssem
LOCKED BY
XGATE
csem
Chapter 10 XGATE (S12XGATEV3)
377