i need your help

[pierre2030]

hi,i am final year student.
-i am doing a final year project named DWOC(digital wireless optical communication).
-inside this project, i am using a PIC16f877A to do the modulation job(manchester coding).
-i will transfer my data from pc via RS232 to my PIC before the data transmit to my receiver.
-i'm using PICbasic to write the programme for the PIC.
-i got one question need your help is how can i send a big size file(around 100kbyte) to the PIC for modulation proccess.
-so far i only can send a 1 byte data to the PIC if i using this programme below

MYDATA var Byte


HSERIN [MYDATA]
HSEROUT ["ENTERED VALUE: ",MYDATA,13,10]
HSEROUT ["ENCODING TO MANCHESTER NOW",13,10]
GOSUB EncodeManchester
HSEROUT ["ENCODING COMPLETED",13,10]
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-what i should modify for the programme in order to achive the aim(100kbyte)?

thank u