Renesas R8C/17 Manual de usuario descargar pdf (Pagina 26)

QDK™

R8C/Tau-NC30

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(4) The

l_nTimerA1Underflows

variable is used to count the number of underflows (transitions

0x0000 -> 0xFFFF) of the 16-bit TimerA1. This variable is used to generate 32-bit timestamp.

(5) The

QS_onStartup()

callback performs the initialization of QS

(6) The QS trace buffer is statically allocated to the specified size

(7) You always need to call

QS_initBuf()

from

QS_onStartup()

to initialize the trace buffer. This

particular QS port initializes UART for data transfer at the given baud rate (

BAUD_RATE = 115200

bits per second)

(8) UARTA0 is configured.

(9) Timer RD is configured as a free-running counter running from f8 (f1/8 = 20MHz/8), which

works out to 0.4 µs per the least-significant bit of this counter.

(10) The QS filters are configured.

(11) Return 1 from

QS_onStartup()

callback means that configuration of QS output was successfull.

(12) The

QS_onCleanup()

callback performs the cleanup of QS. Here nothing needs to be done.

(13) The

QS_onFlush()

callback flushes the QS trace buffer to the host. Typically, the function busy-

waits for the transfer to complete. It is only used in the initialization phase for sending the QS

dictionary records to the host (see Chapter 11 in [PSiCC2])

(14) The

QS_getTime()

callback provides the time-stamp to the QS trace records. The QS time-

stamping implementation uses Timer A1.

(15) Here the interrupt request flag is tested to find out whether Timer RD rolled over. This flag

being set means that the timer rolled over from 0x0000 to 0xFFFF.

(16-17) In case of the rollover the number of underflows must be incremented and the flag is

cleared.

(18) The 32-bit timestamp is the combination of the rollover counter (the coarse time) and the cur-

rent value of the Timer RD counter (the fine time). Please note that the 16-bit Timer RD

counter is subtracted from the coarse time, because the counter counts down.

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