Sharp PC-1500 Technical Reference Manual page 76

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(f) MSK register
MSK
1 6
s.
4 3
xl x !x lx l
..__.__.__.___.'-;-'-1-;""'":::'. _ _,. ,
Interrupt
mas~
bit for IRQ
' - - - - l > )• [
lnte(t upt 1nask bit
fo r
PB7
~
Interrupt mask bit for receii.•er flag RD
'------~) ~ rllerr upl
n1ask bit fot 1ransmittcr flag TD
Interrupt enabled \'.'tlen tt1e bit is ··1".
T he MSK
rcgi~tcr
can read / write data when register is selected (IOIO).
-
-
NOTE: Whan the c on1ents of the MSK register are read. the contents of C L 1, SD1, PB7 . and
IRO
ate
stored i n h igh
o tder
d igi1 positions.
**
CLI $01 PB7 IRQ
M~K M~K
MfK MgK
Contents of MSK read
@ IF register
IF
7 6 5 4 3 2 1 0
1 x 1 x 1 x 1 x 1
TO
[RO]"Tn 1 ~1
I
I '--)
Set at the rising edge of IRQ in put.
.
~. --~>
Set at the rising e<lge of PB7 i nput.
'--- - - -:>
Set upon completion of serial inpu t receive.
RO
is reset \•1hcn
the CPU received data is
read or 1he co1 Hents of the U < egister
are tead.
Set
upo1) con) pletio o ot setial
data
transmission.
Reset \Vhen the CJ 'lU load th e transferfing
serial data to the L register.
IFO and I Fl can read/ write data when register is selected (IOI I).
RD and T D are dedicated to read only.
NOI E: During
H. ~ ceive
ot serial data, RO is reset. Ter m " serial data rcceive" means the period
during which an 8-bi1 data is in reception. \Vhh the start b it excl uded.
©
ODA
~g i ster
DOA
., 6
s
CCf
4
3
Z
I 0
l_J_l_l_i_I
T he register used to determine the direction of the port PA.
i-lh bil of lhe ODA register
When 0
PAi is in thP. input mode.
When 1
PAi i s i n the o utput rnode and 01..11pu ts the content s o O P i.
DDA can read / write when the register is selected (1 100).
71
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