Section 11 16-Bit Cycle Measurement Timer (TCM)
Rev. 1.00 Apr. 28, 2008 Page 309 of 994
REJ09B0452-0100
11.3.1
TCM Timer Counter (TCMCNT)
TCMCNT is a 16-bit readable/writable up-counter. The input clock is selected by the bits CKS2 to
CKS0 in TCMCR. When CKS2 to CKS0 are set to B'111, the external clock is selected. In this
case, the rising or falling edge is selected by CKSEG in TCMCR.
When TCMCNT overflows (counting changes the value from H'FFFF to H'0000), OVF in
TCMCSR is set to 1. When the CST bit in TCMCR is cleared in timer mode, TCMCR is
initialized to H'0000. In cycle measurement mode, TCMCNT is cleared by detection of the first
edge (the edge selected with the IEDG bit in TCMCR) of the measurement period (one period of
the input waveform forms one measurement period).
In timer mode, TCMCNT is always writable. TCMCNT cannot be modified in cycle measurement
mode. TCMCNT should always be accessed in 16-bit units and cannot be accessed in 8-bit units.
TCMCNT is initialized to H'0000.
11.3.2 TCM
Cycle
Upper
Limit Register (TCMMLCM)
TCMMLCM is a 16-bit readable/writable register. TCMMLCM is available as a compare match
register when the TCMMDS bit in TCMCR is cleared (operation is in timer mode). TCMMLCM
is available as a cycle upper limit register when the TCMMDS bit in TCMCR is set to 1 (operation
is in cycle measurement mode).
In timer mode, the value in TCMMLCM is constantly compared with that in TCMCNT, when the
values match, CMF in TCMCSR is set to 1. However, comparison is disabled in the second half of
a cycle of writing to TCMMLCM.
In cycle measurement mode, a value that sets an upper limit on the measurement period can be set
in TCMMLCM. When the second edge (first edge of the following cycle) of the measurement
period is detected, the value in TCMCNT is transferred to TCMICR. At this time, the values in
TCMICR and TCMMLCM are compared. The MAXOVF flag in TCMCSR is set to 1 if the value
in TCMICR is greater than that in TCMMLCM. TCMMLCM should always be accessed in 16-bit
units and cannot be accessed in 8-bit units. TCMMLCM is initialized to H'FFFF.
Summary of Contents for H8S/2100 Series
Page 2: ...Rev 1 00 Apr 28 2008 Page ii of xxvi...
Page 54: ...Section 1 Overview Rev 1 00 Apr 28 2008 Page 28 of 994 REJ09B0452 0100...
Page 92: ...Section 2 CPU Rev 1 00 Apr 28 2008 Page 66 of 994 REJ09B0452 0100...
Page 158: ...Section 5 Interrupt Controller Rev 1 00 Apr 28 2008 Page 132 of 994 REJ09B0452 0100...
Page 244: ...Section 8 8 Bit PWM Timer PWMU Rev 1 00 Apr 28 2008 Page 218 of 994 REJ09B0452 0100...
Page 330: ...Section 10 16 Bit Timer Pulse Unit TPU Rev 1 00 Apr 28 2008 Page 304 of 994 REJ09B0452 0100...
Page 416: ...Section 13 8 Bit Timer TMR Rev 1 00 Apr 28 2008 Page 390 of 994 REJ09B0452 0100...
Page 612: ...Section 18 I 2 C Bus Interface IIC Rev 1 00 Apr 28 2008 Page 586 of 994 REJ09B0452 0100...
Page 706: ...Section 20 LPC Interface LPC Rev 1 00 Apr 28 2008 Page 680 of 994 REJ09B0452 0100...
Page 752: ...Section 21 FSI Interface Rev 1 00 Apr 28 2008 Page 726 of 994 REJ09B0452 0100...
Page 774: ...Section 23 RAM Rev 1 00 Apr 28 2008 Page 748 of 994 REJ09B0452 0100...
Page 1008: ...Section 28 Electrical Characteristics Rev 1 00 Apr 28 2008 Page 982 of 994 REJ09B0452 0100...
Page 1020: ...Rev 1 00 Apr 28 2008 Page 994 of 994 REJ09B0452 0100...
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Page 1024: ...H8S 2117R Group Hardware Manual...