The Nintendo fixed-point digital signal processor (DSP) chip allowed for fast vector-based calculations, bitmap conversions, both 2D and 3D coordinate transformations, and other functions. Four revisions of the chip exist, each physically identical but with different microcode. The DSP-1 version, including the later 1A and 1B bug fix revisions, is used most often; the DSP-2, DSP-3, and DSP-4 are used in only one game each. Similar to the 5A22 CPU in the console, the SA-1 chip contains a 65c816 processor core clocked at 10 MHz, a memory mapper, DMA, decompression and bitplane conversion circuitry, several programmable timers, and CIC region lockout functionality. In Japan, games could be downloaded cheaper than standard cartridges, from Nintendo Power kiosks onto special cartridges containing flash memory and a MegaChips MX15001TFC chip. The chip manages communication with the kiosks to download ROM images, and has an initial menu to select a game. Some were published both in cartridge and download form, while others were download only. The service closed on February 8, 2007. Many cartridges contain other enhancement chips, most of which were created for use by a single company in a few games; the only limitations are the speed of the SNES itself to transfer data from the chip and the current limit of the console. Like the NES before it, the SNES has retained a long-lived fan base. It has continued to thrive on the second-hand market, emulators, and remakes. The SNES has taken the same revival path as the NES. Emulation projects began with the initial release of VSMC in 1994, and Super Pasofami became the first working SNES emulator in 1996. During that time, two competing emulation projects—Snes96 and Snes97—merged to form Snes9x. In 1997, SNES enthusiasts began programming an emulator named ZSNES. In 2004, higan began development as bsnes, in an effort to emulate the system as closely as possible. Nintendo of America took the same stance against the distribution of SNES ROM image files and the use of emulators as it did with the NES, insisting that they represented flagrant software piracy. Proponents of SNES emulation cite discontinued production of the SNES constituting abandonware status, the right of the owner of the respective game to make a personal backup via devices such as the Retrode, space shifting for private use, the desire to develop homebrew games for the system, the frailty of SNES ROM cartridges and consoles, and the lack of certain foreign imports.