Maxim Integrated 71M6513H Power Meter IC Family Software - Manual (Page 50)

71M651x Software User’s Guide
BEGIN_CE_CRITICAL
_SECTION
ce_busy_isr()
sag_data = *((U08x
*)&cestatus);
Disable CE interrupts
stretch clock 6 times
Normal clock
execute Timer expired
function.
(sag_data & 0x0E) !=
0
CE =
(CE2&~CHOP_EN)|CHOP_EN
#ifdef SAGDETECT
CLK_STRETCH
CLK_RELAX
read CE status
END_CE_CRITICAL
_SECTION
user SAG handling code
sag_data = 0
EX_CE_BUSY = 0
EX_CE_BUSY = 0
END
N
N
disable interrupt
disable interrupt
Figure 5-8: CE_BUSY ISR
XFER_BUSY Interrupt
XFER Busy interrupt is requested by the CE at the conclusion of every accumulation cycle. The interrupt service
routine copies the CE output data to the MPU data RAM for further processing by the MPU, which is performed by the
background task. The handling of data for the generation of pulses is also managed in this ISR.
XFER_Busy waits until the second interrupt after one second has elapsed, since it takes roughly one second for the
PLL in the CE to settle and (therefore) for the filtering to be reliable.
The copy operations CE  X and X  CE stated in the flow chart are implemented with the memcpy_cex() and
memcpy_xce() routines, which move data between XRAM and CE DRAM or vice versa. Due to the wait states that
apply to accesses of CE DRAM, this operation cannot be done directly. Using memcpy_cex(), data is moved from
XRAM to CE DRAM, with memcpy_xce(), data is moved from CE DRAM to XRAM.
Revision 2.4 TERIDIAN Proprietary 50 of 137
© Copyright 2005-2006 TERIDIAN Semiconductor Corporation