Everdrive N8

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The Everdrive N8 is a Flash Cartridge made by Krikzz. It uses an FPGA to emulate a wide variety of mappers, allowing the user to store a large collection of ROMs on a single SD card and run them on an NES or Famicom.

In addition to NES ROMs, the Everdrive N8 is able to play FDS disk images.

Famicom expansion audio is supported, and on the NES version is output on the EXP 6 expansion pin on the cartridge connector as used by the PowerPak. A simple modification to the NES allows the expansion audio to be mixed with its output.

Specifications:

  • PRG size: 512 KB
  • CHR size: 512 KB

NES product: https://krikzz.com/store/home/31-everdrive-n8-nes.html

Famicom product: https://krikzz.com/store/home/32-everdrive-n8-famicom.html

Mapper compatibility

As of the OS update v1.26 in 2021, the Everdrive N8 supports the following mappers: [1]

000 001 002 003 004 005 006 007 008 009 010 011 012 013 014 015
016 017 018 019 020 021 022 023 024 025 026 027 028 029 030 031
032 033 034 035 036 037 038 039 040 041 042 043 044 045 046 047
048 049 050 051 052 053 054 055 056 057 058 059 060 061 062 063
064 065 066 067 068 069 070 071 072 073 074 075 076 077 078 079
080 081 082 083 084 085 086 087 088 089 090 091 092 093 094 095
096 097 098 099 100 101 102 103 104 105 106 107 108 109 110 111
112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127
128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143
144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159
160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175
176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191
192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207
208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223
224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239
240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255

Known problems:

  • Mapper 71 only supports the memory controller used by FireHawk, all other Mapper 71 games must be reassigned to Mapper 2 to work correctly.

Obsolete Mappers

A few mappers have been created by others to supplement the Everdrive's provided set, but have since been integrated into or replaced by official mappers:

Software development limitations

Aside from mapper incompatibility, there are minor differences between running NES programs on the Everdrive versus a traditional single-game cartridge.

  • The Everdrive does not accurately simulate power-on state. Because power-on always boots the Everdrive menu, RAM and various registers will be initialized to a consistent state before any NES ROM is chosen to run. (Reset state, however, is not affected by this problem.)
  • Open bus behavior may be different in several memory regions that are used by the Everdrive, but would not be connected on a regular cartridge. (forum post)
  • The Everdrive is incompatible with an NES that has the CopyNES modification installed, due to a bus conflict with its boot code.

Everdrive development resources