TMPM370FYDFG Toshiba, TMPM370FYDFG Datasheet - Page 429

• Manufacturer Part Number: TMPM370FYDFG
• Description: Microcontrollers (MCU) MCU w/ ARM Cortex-M3 256K FLASH, 10K RAM
• Manufacturer: Toshiba

Specifications of TMPM370FYDFG

• Processor Series: TX03
• Core: ARM Cortex M3
• 3rd Party Development Tools: MDK-ARM, RL-ARM, ULINK2
• Product Summaries: Summary
• Lead Free: Yes
• Rohs Compatible Product(s): Available
• Rom (kbytes): 256K
• Rom Type: Flash
• Ram (kbytes): 10K
• Number Of Pins: 100
• Package: QFP(14x20)
• Vcc: 5V
• Cpu Mhz: 80
• Ssp (ch) Spi: -
• I2c/sio (ch): -
• Uart/sio (ch): 4
• Usb: -
• Can: -
• Ethernet: -
• External Bus Interface: N
• Cs/wait Controller (ch): -
• Dma Controller: -
• 10-bit Da Converter: -
• 10-bit Ad Converter: -
• 12-bit Ad Converter: 27
• 16-bit Timer / Counter: 8
• Motor / Igbt Control: Vector Engine
• Real Time Clock: -
• Watchdog Timer: Y
• Osc Freq Detect: Y
• Clock Gear: Y
• Low-power Hold Function: -
• Remote Control Interface: -
• Hardware Cec Controller: -
• Comparators: 4
• Low-voltage Detector: Y
• Etm Hardware Trace: 2-bit
• Lead Free Status / Rohs Status: Details

6) Determination of a Serial Operation Mode
When the intended mode is I/O interface mode, the first byte does not have to be 0x30 as long as tAB is
The first byte from the controller determines the serial operation mode. To use UART mode for
communications between the controller and the target board, the controller must first send a value of
0x86 at a desired baud rate to the target board. To use I/O Interface mode, the controller must send a
value of 0x30 at 1/16 the desired baud rate. Fig. 20-4 shows the waveforms for the first byte.
SIO reception disabled, and calculates the intervals of tAB, tAC and tAD. Fig. 20-5 shows a flowchart
describing the steps to determine the intervals of tAB, tAC and tAD. As shown in the flowchart, the boot
program captures timer counts each time a logic transition occurs in the first serial byte. Consequently,
the calculated tAB, tAC and tAD intervals are bound to have slight errors. If the transfer goes at a high
baud rate, the CPU might not be able to keep up with the speed of logic transitions at the serial receive
pin. In particular, I/O Interface mode is more prone to this problem since its baud rate is generally much
higher than that for UART mode. To avoid such a situation, the controller should send the first serial
byte at 1/16 the desired baud rate.
The flowchart in Fig. 20-5 shows how the boot program distinguishes between UART and I/O Interface
modes. If the length of tAB is equal to or less than the length of tCD, the serial operation mode is
determined as UART mode. If the length of tAB is greater than the length of tCD, the serial operation
mode is determined as I/O Interface mode. Bear in mind that if the baud rate is too high or the timer
operating frequency is too low, the timer resolution will be coarse, relative to the intervals between
logic transitions. This becomes a problem due to inherent errors caused by the way in which timer
counts are captured by software; consequently the boot program might not be able to determine the
serial operation mode correctly. To prevent this problem, reset UART mode within the programming
routine.
For example, the serial operation mode may be determined to be I/O Interface mode when the
intended mode is UART mode. To avoid such a situation, when UART mode is utilized, the controller
should allow for a time-out period within which it expects to receive an echo-back (0x86) from the
target board. The controller should give up the communication if it fails to get that echo-back within the
allowed time. When I/O Interface mode is utilized, once the first serial byte has been transmitted, the
controller should send the SCLK clock after a certain idle time to get an acknowledge response. If the
received acknowledge response is not 0x30, the controller should give up further communications.
After
UART (0x86)
I/O Interface
RESET
(0x30)
is released, the boot program monitors the first serial byte from the controller, with the
A
A
Fig. 20-4 Serial Operation Mode Byte
Start
bit 0
tAB
tAC
tAD
bit 0
bit 1
TMPM370 20-37
tAB
tAC
tAD
B
bit 1
bit 2
bit 2
bit 3
C
B
bit 3
bit 4
bit 4
bit 5
tCD
C
bit 5
bit 6
tCD
bit 6
bit 7
Flash Memory Operation
D
D
bit 7
Stop
TMPM370