Original Chip Set#Paula
Paula is one of the custom chips of the Amiga and for the control of the floppy disk drives, serial interface and is responsible for sound output.
The audio part of Paula can cover four voices (Stereo, two left, two right) 8- bit samples to spend. The sampling rate is always an integral part of the system clock and can ( when operating with Direct Memory Access (DMA ) ) depending on the chipset up to 28 kHz (Original Chip Set (OCS ) ) and 56kHz (Enhanced Chip Set (ECS ) in VGA mode ) amount. Outside of the chip a hardwired reconstruction filter was installed. Depending on the Amiga model that has a cutoff frequency in the single digit kilohertz range and is partly (together with the Power LED - share both functions of a control line ) remote controllable via bridging or switchable.
Limiting the sample rate is on the OCS Agnus, the DMA timing does not provide for higher data rate. If the software a higher sampling rate is set, the only causes that the same sample is output repeatedly. Since the output register can be powered not only by DMA, but alternatively by the processor ( CPU) with audio data, higher sampling rates can be achieved only by CPU control - with correspondingly high CPU utilization. With the ECS a higher sampling rate than 28 kHz is also possible via DMA. By coupling the DMA controller with the video timing, this is only possible at a higher line frequency; in VGA mode up to 56 kHz. ECS is set to a conventional television video mode 15.625 KHz line frequency, it can, as well as the OCS providing only data for a sampling rate of 28 kHz.
Although the individual channels have a resolution of 8 bits, it is quite possible through skillful combination of two channels, to increase the resolution to 14 bits or less. Due to hardware tolerances in the D / A converter but the quality is inferior to that of a real 14 -bit resolution. By appropriate calculations of the CPU, it is also possible to increase the channel number of the software. Known for the Tracker Octalyzer and OctaMED, each offering eight channels were.
Paula continues to be responsible for reading and writing DD disks. The need for ordinary HD floppy drives data rates of 500 kilobits per second can not provide the chip. Therefore contain Amiga models with HD drive a special drive that rotates the magnetic disk of HD disks only at half speed, whereby the writing and reading but also is only as fast as DD disks - twice as much time as in ordinary ( PC ) HD drives takes to complete.
For the AGA chipset all the custom chips were revised and improved by Commodore. Only Paula was taken over unchanged from the older models.
KIM- 1 • PET CBM 2001 • 3000 • 4000 • CBM CBM 8000 • MMF 9000
CBM 500 CBM * • 600 • 700 • CBM CBM 900 *
VC 10 VC 20 • • C64 (SX, GS †) • 264 series ( C16, C116, Plus / 4) • C128 • C65 *
1000 Sidecar • • 500 • 2000 • CDTV † • 600 • 1200 • 4000 • • 3000/T/UX CD ³ ² †
• PC-1 PC - 10 and PC -60 • x86LT • A1060
Datasette • CBM floppy drives • VC15xx ( VC1540/41, VC1551, VC1570/71, VC1581 ) • SFD100x ( SFD1001, SFD1002 ) • CBM 2020-8250 • A570 • A590 • A3070
MPS- MPS Series • 801 • 1000 • MPS MPS 1500C • VC1520 • CBM -8000 Series • CBM 4022
Zorro bus • Watches • Port WOM • RAM Expansion Unit • Commodore mouse • monochrome and color monitors • A10 speakers • Multi-User Systems ( MBS)
Writing and desktop calculators • LED watches 2000K/3000H • † • Chessmate
MOS Technology VIC • • VIC II • TED • VDC • SID • PIA • VIA • TPI • CIA • ACIA • Agnus ( blitter, Copper) • Paula • EHB mode • HAM mode
OCS • ECS • AGA
*: Only prototype †: Console
- Sound chip