Sharp PC-1500 - Page 73

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3-1 . Outline
The LH5810 1.H5 81 I 1' a single chip CMOS s tat ic LSI that fca1urcs 1hc follo ,,in g
functions:
(I) two pairs of 8-bit bidirectional pon
(2) o ne pair of 8-bit ou 1pu1 port
(J) two int errup t r~qu es l inputs (one of th em pon input )
(4) one inc
errupt request ou 1p11 1
(5) CPU wait con t ro l
(6) ser ial da ta 1 ran sf cr con crol
3-2. Functions
68
CD Pons PA0 "' 7 and PB0 "-7 can be programmed of thcirda1a now direc tion in bit unit.
Al so. it can be a cccs,cd as one loca 1i on of the memory. as seen from 1 hc CPU.
(j) Laich cloc k 1'<1> can be dir ec 1ly given fr om ch e external sou rce th ro ugh output p orts
PC0"'7 . Also. it can be ac cessed as 011e l oca 1i on of the mem ory. as seen fro m c hc C P U.
CD A~ the re arc 1wo i n1 er rupt r cq ucs1 i nput s o f IRQ and P B7. in1 erru pt request ca n be
i
ssue d 10 1h c CPU at the rising edge of the input when the corresponding bit of the
MSK register is "I" . Pl37 mu~t be in the input mode before u,ing Pll7 for the interrupt
input.
©Since there is the CPU ''aitcontrolcircuit. l\\O memo!! enablc,ign al scan be ou tput to
the memory of slO \\ accc's time. Bc~idc;.. it has t\\O input\ of wait conditions. Up to 8
\'arieties of access t ime can be programmed.
© 11 ha s the following function~ IO handle serial da ta tran, fcr.
A. Serial data tr ansmit
Se rial d ala 1 ra nsfer ta kc~ pla ce in a f or mat o f a st art bit. 8 bits of da 1 11. and l wo sto p
bi1s. Transmis sion clock is sclec1a blc by means of int erna l a nd ex te rna l clock se l ec l
program. as wdl as the clock 11nc ( I I. I 2. I 128, I 256. I 512. I 102 4. I 2048.
a
nd I 4096 of the ba sic clock) .
B. Serial data receive
When th e s ta rt bi1 is rccci\cd in an idle state. the '>crial data follO\\ing to it is
recei,cd. Afla recei\'ing 1hc data comprised of8 hih. i1 i-. then s tored in the internal
register and th e interrupt request flag is set acti\-e . Recci\C clock i~ furnished from
the ex t ernal source '' hich become:. th e rec einng cloc k by i1~c1r. It must be in
,y
nchr o ni 7at io n \1 i1h 1hc ~cria l daia input.
C. Pul se waveform
11 is po ssible to ha ve con 1i nu ou s ou 1 pu 1 of pu bc wa\'cform. Fr eq u enc y is
pr og r ammable lo cigh1 kind, of I I. I 2. I. 128. I 256. I 5 12. I , I 024. I . 20 48 , an d
I 4096 of the ba sic cloc l- .
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