WB_SD_COMMAND
wb_write(wb, WB_SD_COMMAND, cmd->c_opcode);
wb_write(wb, WB_SD_COMMAND, (cmd->c_arg >> 24) & 0xff);
wb_write(wb, WB_SD_COMMAND, (cmd->c_arg >> 16) & 0xff);
wb_write(wb, WB_SD_COMMAND, (cmd->c_arg >> 8) & 0xff);
wb_write(wb, WB_SD_COMMAND, (cmd->c_arg >> 0) & 0xff);