BBC Microcomputer Service Manual Oct 1985 Section 1 BBC Micro ...

QWERTY These are the upper left keys on the keyboard ie refers to
the standard keyboard layout
RA0-2 Row Address lines from the CRTC to access the RAM
RAM Random Access read/write Memory
RAS Row Address Strobe - Control line for the DRAM
RC Resistor Capacitor network
RGB Red Green Blue - individual colour signals for the VDU
ROM Read Only Memory ROMSEL ROM SELect latch
RS423C An internationally defined convention for serial
transmission of data
RTS Ready To Send - control output on RS423 port
SK Socket
SOT Select On Test
SW South West
Taw Tinned Copper Wire
TTL Tranistor Transistor Logic a standard type of digital IC (
74- series)
UHF Ultra High Frequency ` - signal for input to a TV aerial socket
ULA Uncommitted Logic Array - semi-custom IC
VDU Visual Display Unit
VIA Versatile Interface Adaptor (6522)
VR Variable .Resistor
Z80 a' commonly used 8 bit microprocessor
1MHz 1 MegaHertz - usually refers to the - interface bus running
at that speed
1MHzE Strobe to which the processor is synchronised when accessing " slow
devices such as 6522 VIA and 1MHz bus
2MHzF Strobe' to which the processor is synchronised when accessing "
fast" devices such as ROM and DRAMs.
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