extmod: Add initial framebuf module.
diff --git a/extmod/modframebuf.c b/extmod/modframebuf.c
new file mode 100644
index 0000000..d0ef238
--- /dev/null
+++ b/extmod/modframebuf.c
@@ -0,0 +1,205 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include "py/nlr.h"
+#include "py/obj.h"
+#include "py/runtime.h"
+
+#if MICROPY_PY_FRAMEBUF
+
+#include "font_petme128_8x8.h"
+
+// 1-bit frame buffer, each byte is a column of 8 pixels
+typedef struct _mp_obj_framebuf1_t {
+    mp_obj_base_t base;
+    uint8_t *buf;
+    uint16_t width, height, stride;
+} mp_obj_framebuf1_t;
+
+STATIC mp_obj_t framebuf1_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
+    mp_arg_check_num(n_args, n_kw, 3, 4, false);
+
+    mp_obj_framebuf1_t *o = m_new_obj(mp_obj_framebuf1_t);
+    o->base.type = type;
+
+    mp_buffer_info_t bufinfo;
+    mp_get_buffer_raise(args[0], &bufinfo, MP_BUFFER_WRITE);
+    o->buf = bufinfo.buf;
+
+    o->width = mp_obj_get_int(args[1]);
+    o->height = mp_obj_get_int(args[2]);
+    o->stride = o->width;
+    if (n_args >= 4) {
+        o->stride = mp_obj_get_int(args[3]);
+    }
+
+    return MP_OBJ_FROM_PTR(o);
+}
+
+STATIC mp_obj_t framebuf1_fill(mp_obj_t self_in, mp_obj_t col_in) {
+    mp_obj_framebuf1_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_int_t col = mp_obj_get_int(col_in);
+    if (col) {
+        col = 0xff;
+    }
+    for (int y = 0; y < self->height / 8; ++y) {
+        memset(self->buf + y * self->stride, col, self->width);
+    }
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(framebuf1_fill_obj, framebuf1_fill);
+
+STATIC mp_obj_t framebuf1_pixel(size_t n_args, const mp_obj_t *args) {
+    mp_obj_framebuf1_t *self = MP_OBJ_TO_PTR(args[0]);
+    mp_int_t x = mp_obj_get_int(args[1]);
+    mp_int_t y = mp_obj_get_int(args[2]);
+    if (0 <= x && x < self->width && 0 <= y && y < self->height) {
+        int index = (y / 8) * self->stride + x;
+        if (n_args == 3) {
+            // get
+            return MP_OBJ_NEW_SMALL_INT(self->buf[index] >> (y & 7));
+        } else {
+            // set
+            if (mp_obj_get_int(args[3])) {
+                self->buf[index] |= (1 << (y & 7));
+            } else {
+                self->buf[index] &= ~(1 << (y & 7));
+            }
+        }
+    }
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(framebuf1_pixel_obj, 3, 4, framebuf1_pixel);
+
+STATIC mp_obj_t framebuf1_scroll(mp_obj_t self_in, mp_obj_t xstep_in, mp_obj_t ystep_in) {
+    mp_obj_framebuf1_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_int_t xstep = mp_obj_get_int(xstep_in);
+    mp_int_t ystep = mp_obj_get_int(ystep_in);
+    if (xstep == 0 && ystep > 0) {
+        for (int y = self->height / 8; y > 0;) {
+            --y;
+            for (int x = 0; x < self->width; ++x) {
+                int prev = 0;
+                if (y > 0) {
+                    prev = (self->buf[(y - 1) * self->stride + x] >> (8 - ystep)) & ((1 << ystep) - 1);
+                }
+                self->buf[y * self->stride + x] = (self->buf[y * self->stride + x] << ystep) | prev;
+            }
+        }
+    } else if (xstep == 0 && ystep < 0) {
+        for (int y = 0; y < self->height / 8; ++y) {
+            for (int x = 0; x < self->width; ++x) {
+                int prev = 0;
+                if (y + 1 < self->height / 8) {
+                    prev = self->buf[(y + 1) * self->stride + x] << (8 + ystep);
+                }
+                self->buf[y * self->stride + x] = (self->buf[y * self->stride + x] >> -ystep) | prev;
+            }
+        }
+    }
+    // TODO xstep!=0
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_3(framebuf1_scroll_obj, framebuf1_scroll);
+
+STATIC mp_obj_t framebuf1_text(size_t n_args, const mp_obj_t *args) {
+    // extract arguments
+    mp_obj_framebuf1_t *self = MP_OBJ_TO_PTR(args[0]);
+    const char *str = mp_obj_str_get_str(args[1]);
+    mp_int_t x0 = mp_obj_get_int(args[2]);
+    mp_int_t y0 = mp_obj_get_int(args[3]);
+    mp_int_t col = 1;
+    if (n_args >= 5) {
+        col = mp_obj_get_int(args[4]);
+    }
+
+    // loop over chars
+    for (; *str; ++str) {
+        // get char and make sure its in range of font
+        int chr = *(uint8_t*)str;
+        if (chr < 32 || chr > 127) {
+            chr = 127;
+        }
+        // get char data
+        const uint8_t *chr_data = &font_petme128_8x8[(chr - 32) * 8];
+        // loop over char data
+        for (int j = 0; j < 8; j++, x0++) {
+            if (0 <= x0 && x0 < self->width) { // clip x
+                uint vline_data = chr_data[j]; // each byte is a column of 8 pixels, LSB at top
+                for (int y = y0; vline_data; vline_data >>= 1, y++) { // scan over vertical column
+                    if (vline_data & 1) { // only draw if pixel set
+                        if (0 <= y && y < self->height) { // clip y
+                            uint byte_pos = x0 + self->stride * ((uint)y >> 3);
+                            if (col == 0) {
+                                // clear pixel
+                                self->buf[byte_pos] &= ~(1 << (y & 7));
+                            } else {
+                                // set pixel
+                                self->buf[byte_pos] |= 1 << (y & 7);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(framebuf1_text_obj, 4, 5, framebuf1_text);
+
+STATIC const mp_rom_map_elem_t framebuf1_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_fill), MP_ROM_PTR(&framebuf1_fill_obj) },
+    { MP_ROM_QSTR(MP_QSTR_pixel), MP_ROM_PTR(&framebuf1_pixel_obj) },
+    { MP_ROM_QSTR(MP_QSTR_scroll), MP_ROM_PTR(&framebuf1_scroll_obj) },
+    { MP_ROM_QSTR(MP_QSTR_text), MP_ROM_PTR(&framebuf1_text_obj) },
+};
+STATIC MP_DEFINE_CONST_DICT(framebuf1_locals_dict, framebuf1_locals_dict_table);
+
+STATIC const mp_obj_type_t mp_type_framebuf1 = {
+    { &mp_type_type },
+    .name = MP_QSTR_FrameBuffer1,
+    .make_new = framebuf1_make_new,
+    .locals_dict = (mp_obj_t)&framebuf1_locals_dict,
+};
+
+STATIC const mp_rom_map_elem_t framebuf_module_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_framebuf) },
+    { MP_ROM_QSTR(MP_QSTR_FrameBuffer1), MP_ROM_PTR(&mp_type_framebuf1) },
+};
+
+STATIC MP_DEFINE_CONST_DICT(framebuf_module_globals, framebuf_module_globals_table);
+
+const mp_obj_module_t mp_module_framebuf = {
+    .base = { &mp_type_module },
+    .name = MP_QSTR_framebuf,
+    .globals = (mp_obj_dict_t*)&framebuf_module_globals,
+};
+
+#endif // MICROPY_PY_FRAMEBUF
diff --git a/py/builtin.h b/py/builtin.h
index e3e68e1..35d8910 100644
--- a/py/builtin.h
+++ b/py/builtin.h
@@ -106,6 +106,7 @@
 extern const mp_obj_module_t mp_module_machine;
 extern const mp_obj_module_t mp_module_lwip;
 extern const mp_obj_module_t mp_module_websocket;
+extern const mp_obj_module_t mp_module_framebuf;
 
 // extmod functions
 MP_DECLARE_CONST_FUN_OBJ(pyb_mount_obj);
diff --git a/py/mpconfig.h b/py/mpconfig.h
index 6c2db2f..bbf0555 100644
--- a/py/mpconfig.h
+++ b/py/mpconfig.h
@@ -845,6 +845,10 @@
 #define MICROPY_PY_WEBSOCKET (0)
 #endif
 
+#ifndef MICROPY_PY_FRAMEBUF
+#define MICROPY_PY_FRAMEBUF (0)
+#endif
+
 /*****************************************************************************/
 /* Hooks for a port to add builtins                                          */
 
diff --git a/py/objmodule.c b/py/objmodule.c
index 5fd7b82..d2a4d89 100644
--- a/py/objmodule.c
+++ b/py/objmodule.c
@@ -196,6 +196,9 @@
 #if MICROPY_PY_WEBSOCKET
     { MP_ROM_QSTR(MP_QSTR_websocket), MP_ROM_PTR(&mp_module_websocket) },
 #endif
+#if MICROPY_PY_FRAMEBUF
+    { MP_ROM_QSTR(MP_QSTR_framebuf), MP_ROM_PTR(&mp_module_framebuf) },
+#endif
 
     // extra builtin modules as defined by a port
     MICROPY_PORT_BUILTIN_MODULES
diff --git a/py/py.mk b/py/py.mk
index 899f333..3cfc671 100644
--- a/py/py.mk
+++ b/py/py.mk
@@ -170,6 +170,7 @@
 	../extmod/modussl.o \
 	../extmod/modurandom.o \
 	../extmod/modwebsocket.o \
+	../extmod/modframebuf.o \
 	../extmod/fsusermount.o \
 	../extmod/vfs_fat.o \
 	../extmod/vfs_fat_ffconf.o \
diff --git a/py/qstrdefs.h b/py/qstrdefs.h
index f5e06f1..d8c7ccc 100644
--- a/py/qstrdefs.h
+++ b/py/qstrdefs.h
@@ -761,3 +761,12 @@
 #if MICROPY_PY_WEBSOCKET
 Q(websocket)
 #endif
+
+#if MICROPY_PY_FRAMEBUF
+Q(framebuf)
+Q(FrameBuffer1)
+Q(fill)
+Q(pixel)
+Q(scroll)
+Q(text)
+#endif
diff --git a/stmhal/font_petme128_8x8.h b/stmhal/font_petme128_8x8.h
index 8df78a2..7f928ed 100644
--- a/stmhal/font_petme128_8x8.h
+++ b/stmhal/font_petme128_8x8.h
@@ -24,7 +24,7 @@
  * THE SOFTWARE.
  */
 
-const uint8_t font_petme128_8x8[] = {
+static const uint8_t font_petme128_8x8[] = {
     0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, // 32= 
     0x00,0x00,0x00,0x4f,0x4f,0x00,0x00,0x00, // 33=!
     0x00,0x07,0x07,0x00,0x00,0x07,0x07,0x00, // 34="